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man pages section 8: System Administration Commands

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Updated: Thursday, June 13, 2019
 
 

zfs(8)

Name

zfs - configures ZFS file systems

Synopsis

zfs [-?]
zfs help subcommand | help | property property-name | permission
zfs help -l properties
zfs allow filesystem
|volume
zfs allow [-ldug] 
everyone|user|group[,...] 
perm|@setname[,...] 
     filesystem|volume
zfs allow [-ld] 
-e perm|@setname[,...] 
filesystem|volume
zfs allow -c 
perm|@setname[,...] filesystem
|volume
zfs allow -s @
setname perm|@setname[,...] 
filesystem|volume
zfs clone [-p] [
-K] [-o property=
value] ... snapshot filesystem
|volume
zfs create [-p] [
-o property=value] ... 
filesystem
zfs create [-ps] [
-b blocksize] [-o 
property=value] ... -V 
size volume
zfs destroy [-rRsf] 
filesystem|volume
zfs destroy [-rRsd] 
snapshot
zfs destroy share
zfs diff [-FHNqrte] [
-o field] ... snapshot [
snapshot|filesystem]
zfs diff -E [
-FHqrt] [-o field] ... 
snapshot|filesystem
zfs get [-rHpe|
-d max][-o all | 
field[,...]] [-s source[,...]]
     all | property[,...] filesystem|
volume|snapshot|share ...
zfs get share [filesystem
]
zfs groupspace [-hniHp] [
-o field[,...]] [-sS 
field] ...
     [-t type [,...]] 
filesystem|snapshot
zfs hold [-r] 
tag snapshot...
zfs holds [-r] 
snapshot...
zfs key -l {
-a | [-r] filesystem|
volume}
zfs key -u [
-f] {-a | [-r] filesystem
|volume}
zfs key -c [
-o keysource=value] {
-a | [-r] filesystem|
volume}
zfs key -K {
-a | [-r] filesystem|
volume}
zfs list [-rH|
-d max][-o property
[,...]] [-t type[,...]] [-I state,..]
     [-s property] ... [-S
 property] ...
     [filesystem|volume|
snapshot|share|path] ...
zfs inherit [-rS] 
property filesystem|volume|snapshot|share
 ...
zfs mount 
zfs mount [-vO] [
-o options] -a | 
filesystem
zfs promote clone-filesystem
zfs receive [-vnFu] [[
-o property=value] | [
-x property]] ...
     filesystem|volume|
snapshot
zfs receive [-vnFu] [[
-o property=value] | [
-x property]] ...
     [-d | -e] filesystem
zfs receive -C <filesystem|volume>
zfs release [-r] 
tag snapshot...
zfs rename filesystem
|volume|snapshot 
     filesystem|volume|
snapshot
zfs rename [-p] 
filesystem|volume filesystem
|volume
zfs rename -r 
snapshot snapshot
zfs rename share 
share
zfs rollback [-rRf] 
snapshot
zfs send [-vbpnC] [-[Rr[c]]] [-w compress|none]
        [-D [-m <memsize>]] 
        [-[iI] <snapshot>] [-s <subopt>] <snapshot> 
zfs set [-r] 
property=value filesystem|
volume|snapshot ...
zfs share -u [-o property=value] 
filesystem%share
zfs share filesystem|mountpoint|filesystem%share
zfs share -a| -r | 
filesystem
zfs snapshot [-r] [
-o property=value]... 
      filesystem@snapname|volume@snapname
zfs unmount [-f] 
-a | filesystem|mountpoint
zfs unshare filesystem
|mountpoint|filesystem%share
zfs unshare -a| 
-r filesystem|
zfs upgrade
zfs upgrade [-v]
zfs upgrade [-r] [
-V version] -a | 
filesystem
zfs userspace [-hniHp] [
-o field[,...]] [-sS 
field] ...
     [-t type [,...]] 
filesystem|snapshot
zfs unallow [-rldug] 
everyone|user|group[,...] [
perm|@setname[,... ]] 
     filesystem|volume
zfs unallow [-rld] 
-e [perm|@setname[,... ]] 
filesystem|volume
zfs unallow [-r] 
-c [perm|@setname[ ... ]] 
filesystem|volume
zfs unallow [-r] 
-s @setname [perm|@
setname[,... ]] filesystem|
volume

Description

The zfs command configures ZFS datasets within a ZFS storage pool, as described in zpool(8). A dataset is identified by a unique path within the ZFS namespace. For example:

pool/{filesystem,volume,
snapshot}

where the maximum length of a dataset name is MAXNAMELEN (256 bytes).

A dataset can be one of the following:

file system

A ZFS dataset of type filesystem can be mounted within the standard system namespace and behaves like other file systems. While ZFS file systems are designed to be POSIX compliant, known issues exist that prevent compliance in some cases. Applications that depend on standards conformance might fail due to nonstandard behavior when checking free file system space.

volume

A logical volume exported as a raw or block device. This type of dataset should only be used under special circumstances. File systems are typically used in most environments.

snapshot

A read-only version of a file system or volume at a given point in time. It is specified as filesystem@name or volume@name.

ZFS File System Hierarchy

A ZFS storage pool is a logical collection of devices that provide space for datasets. A storage pool is also the root of the ZFS file system hierarchy.

The root of the pool can be accessed as a file system, such as mounting and unmounting, taking snapshots, and setting properties. The physical storage characteristics, however, are managed by the zpool(8) command.

See zpool(8) for more information on creating and administering pools.

Snapshots

A snapshot is a read-only copy of a file system or volume. Snapshots can be created extremely quickly, and initially consume no additional space within the pool. As data within the active dataset changes, the snapshot consumes more data than would otherwise be shared with the active dataset.

Snapshots can have arbitrary names. Snapshots of volumes can be cloned or rolled back, but cannot be accessed independently.

File system snapshots can be accessed under the .zfs/snapshot directory in the root of the file system. Snapshots are automatically mounted on demand and may be unmounted at regular intervals. The visibility of the .zfs directory can be controlled by the snapdir property.

Clones

A clone is a writable volume or file system whose initial contents are the same as another dataset. As with snapshots, creating a clone is nearly instantaneous, and initially consumes no additional space.

Clones can only be created from a snapshot. When a snapshot is cloned, it creates an implicit dependency between the parent and child. Even though the clone is created somewhere else in the dataset hierarchy, the original snapshot cannot be destroyed as long as a clone exists. The origin property exposes this dependency, and the destroy command lists any such dependencies, if they exist.

The clone parent-child dependency relationship can be reversed by using the promote subcommand. This causes the “origin” file system to become a clone of the specified file system, which makes it possible to destroy the file system that the clone was created from.

Mount Points

Creating a ZFS file system is a simple operation, so the number of file systems per system is likely to be numerous. To cope with this, ZFS automatically manages mounting and unmounting file systems without the need to edit the /etc/vfstab file. All automatically managed file systems are mounted by ZFS at boot time.

By default, file systems are mounted under /path, where path is the name of the file system in the ZFS namespace. Directories are created and destroyed as needed.

A file system can also have a mount point set in the mountpoint property. This directory is created as needed, and ZFS automatically mounts the file system when the zfs mount -a command is invoked (without editing /etc/vfstab). The mountpoint property can be inherited, so if pool/home has a mount point of /export/stuff, then pool/home/user automatically inherits a mount point of /export/stuff/user.

A file system can be mounted temporarily at a location other than the file systems persistent mount point by specifying the –o mountpoint=value option to the zfs mount command. This is only permitted for file systems with non-legacy mount points.

A file system mountpoint property of none prevents the file system from being mounted.

If needed, ZFS file systems can also be managed with traditional tools (mount, umount, /etc/vfstab). If a file system's mount point is set to legacy, ZFS makes no attempt to manage the file system, and the administrator is responsible for mounting and unmounting the file system.

Zones

The physical properties of an added file system are controlled by the global administrator. However, the zone administrator can create, modify, or destroy files within the added file system, depending on how the file system is mounted.

A dataset can also be delegated to a non-global zone by using the zonecfg add dataset subcommand. You cannot delegate a dataset to one zone and the children of the same dataset to another zone. The zone administrator can change properties of the dataset or any of its children. However, the quota property is controlled by the global administrator.

A ZFS volume can be added as a device to a non-global zone by using the zonecfg add device subcommand. However, its physical properties can be modified only by the global administrator.

For more information about zonecfg syntax, see the zonecfg(8) man page.

After a dataset is delegated to a non-global zone, the zoned property is automatically set. A zoned file system can only be mounted in the global zone by using a temporary mountpoint property (see “Temporary Mount Point Properties”).

The global administrator can forcibly clear the zoned property, though this should be done with extreme care. The global administrator should verify that all the mount points are acceptable before clearing the property.

Deduplication

Deduplication is the process of removing redundant data at the block-level, reducing the total amount of data stored. Deduplication is pool-wide; each dataset can opt in or out using its own dedup property. If a file system has the dedup property enabled, duplicate data blocks are removed synchronously on write. The result is that only unique data are stored and common components are shared among files in all datasets in the pool that have dedup enabled.

Encryption

For a full description of ZFS encryption and the ZFS encryption syntax, see zfs_encrypt(8).

Native Properties

Properties are divided into two types, native properties and user-defined (or user) properties. Native properties either provide internal statistics or control ZFS behavior. In addition, native properties are either editable or read-only. User properties have no effect on ZFS behavior, but you can use them to annotate datasets in a way that is meaningful in your environment. For more information about user properties, see the “User Properties” section, below.

Every dataset has a set of properties that provide statistics about the dataset as well as control various behaviors. Properties are inherited from the parent unless overridden by the child. Some properties apply only to certain types of datasets (file systems, volumes, or snapshots).

The values of numeric properties can be specified using human-readable suffixes (for example, k, KB, M, Gb, and so forth, up to Z for zettabyte). The following are all valid (and equal) specifications:

1536M, 1.5g, 1.50GB

The values of non-numeric properties are case-sensitive and must be lowercase, except for the mountpoint property.

The following native properties consist of read-only statistics about the dataset. These properties can be neither set, nor inherited. Native properties apply to all dataset types unless otherwise noted.

available

The amount of space available to the dataset and all its children, assuming that there is no other activity in the pool. Because space is shared within a pool, availability can be limited by any number of factors, including physical pool size, quotas, reservations, or other datasets within the pool.

This property can also be referred to by its shortened column name, avail.

compressratio

The compression ratio achieved for this dataset, expressed as a multiplier. Compression can be turned on by running: zfs set compression=on dataset. The default value is off.

creation

The time this dataset was created.

defer_destroy

This property is on if the snapshot has been marked for deferred destroy by using the zfs destroy –d command. Otherwise, the property is off.

keychangedate

For more information, see zfs_encrypt(8).

keystatus

For more information, see zfs_encrypt(8).

mounted

For file systems, indicates whether the file system is currently mounted. This property can be either yes or no.

origin

For cloned file systems or volumes, the snapshot from which the clone was created. The origin cannot be destroyed (even with the –r or –f options) so long as a clone exists.

referenced

The amount of data that is accessible by this dataset, which may or may not be shared with other datasets in the pool. When a snapshot or clone is created, it initially references the same amount of space as the file system or snapshot it was created from, since its contents are identical.

This property can also be referred to by its shortened column name, refer.

rekeydate

For more information, see zfs_encrypt(8).

type

The type of dataset: filesystem, volume, or snapshot.

used

The amount of space consumed by this dataset and all its descendents. This is the value that is checked against this dataset's quota and reservation. The space used does not include this dataset's reservation, but does take into account refreservation (through usedbyrefreservation) and the reservations of any descendent datasets (through usedbychildren). The amount of space that a dataset consumes from its parent, as well as the amount of space that are freed if this dataset is recursively destroyed, is the greater of its space used and its reservation.

When snapshots (see the “Snapshots” section) are created, their space is initially shared between the snapshot and the file system, and possibly with previous snapshots. As the file system changes, space that was previously shared becomes unique to the snapshot, and counted in the snapshot's space used. Additionally, deleting snapshots can increase the amount of space unique to (and used by) other snapshots.

The amount of space used, available, or referenced does not take into account pending changes. Pending changes are generally accounted for within a few seconds. Committing a change to a disk using fsync(3C) or O_SYNC does not necessarily guarantee that the space usage information is updated immediately.

usedby*

The usedby* properties decompose the used properties into the various reasons that space is used. Specifically, used = usedbychildren + usedbydataset + usedbyrefreservation +, usedbysnapshots. These properties are only available for datasets created on pools that are version 13 or higher.

usedbychildren

The amount of space used by children of this dataset, which would be freed if all the dataset's children were destroyed.

usedbydataset

The amount of space used by this dataset itself, which would be freed if the dataset was destroyed (after first removing any refreservation and destroying any necessary snapshots or descendents).

usedbyrefreservation

The amount of space used by a refreservation set on this dataset, which would be freed if the refreservation was removed.

Space accounted for by this property represents potential consumption by future writes, reserved in advance to prevent write allocation failures in this dataset. This can include unwritten data, space currently shared with snapshots, and compression savings for volumes (which may be lost when replaced with less compressible data). When allocations for later writes increase usedbydataset or usedbysnapshots, usedbyrefreservation will decrease accordingly.

usedbysnapshots

The amount of space consumed by snapshots of this dataset. In particular, it is the amount of space that would be freed if all of this dataset's snapshots were destroyed. Note that this is not simply the sum of the snapshots' used properties because space can be shared by multiple snapshots.

userused@user

The amount of space consumed by the specified user in this dataset. Space is charged to the owner of each file, as displayed by ls –l. The amount of space charged is displayed by du and ls –s. See the zfs userspace subcommand for more information.

Unprivileged users can access only their own space usage. The root user, or a user who has been granted the userused privilege with zfs allow, can access everyone's usage.

The userused@... properties are not displayed by zfs get all. The user's name must be appended after the @ symbol, using one of the following forms:

  • POSIX name (for example, joe)

  • POSIX numeric ID (for example, 789)

  • SID name (for example, joe.smith@mydomain )

  • SID numeric ID (for example, S-1-123-456-789)

userrefs

This property is set to the number of user holds on this snapshot. User holds are set by using the zfs hold command.

groupused@group

The amount of space consumed by the specified group in this dataset. Space is charged to the group of each file, as displayed by ls –l. See the userused@user property for more information.

Unprivileged users can only access their own groups' space usage. The root user, or a user who has been granted the groupused privilege with zfs allow, can access all groups' usage.

volblocksize=blocksize

For volumes, specifies the block size of the volume. The blocksize cannot be changed once the volume has been written, so it should be set at volume creation time. The default blocksize for volumes is 8 KB. Any power of 2 from 512 bytes to 1 MB is valid.

This property can also be referred to by its shortened column name, volblock.

effectivereadlimit
effectivewritelimit

These properties provide a view of what the effective limit is on a dataset. The value displayed indicates the maximum throughput the dataset is governed by. The reported effective limit is the lowest data limit at any point between the root and the indicated dataset. See readlimit and writelimit for more details on limit behavior.

The following native properties can be used to change the behavior of a ZFS dataset.

aclmode=discard | mask | passthrough

Controls how an ACL is modified during chmod(2). A file system with an aclmode property of discard (the default) deletes all ACL entries that do not represent the mode of the file. An aclmode property of mask reduces user or group permissions. The permissions are reduced so that they are no greater than the group permission bits, unless it is a user entry that has the same UID as the owner of the file or directory. In this case, the ACL permissions are reduced so that they are no greater than owner permission bits. mask also preserves the ACL across mode changes (without an explicit ACL set [by means of chmod(1)] between the mode changes). A file system with an aclmode property of passthrough indicates that no changes will be made to the ACL other than generating the necessary ACL entries to represent the new mode of the file or directory.

refreservation=size | none | auto

The minimum amount of space guaranteed to a dataset, not including its descendents. The default refreservation is none for file systems.

For ZFS volumes, the refreservation is automatically set to a slightly larger size than the actual volume size to account for ZFS metadata overhead. You can use the dense value to reserve enough space for both data and metadata for the current volume size. For example, if you need more space for other file systems, you can temporarily reduce a volume's refreservation value, which converts this to a sparse volume. Then, you can revert the volume refreservation value back to the original value when it was created by specifying the dense value.

When the usedbydataset space is below this value, the dataset is treated as if it were taking up the amount of space specified by refreservation. The usedbyrefreservation figure represents this extra space, adding to the total used space charged to the dataset, and in turn consuming from the parent datasets' usage, quotas, and reservations. This protects the dataset from overcommitment of pool resources, by ensuring that space for future writes is reserved in advance.

Space shared with snapshots can later be replaced with new data, and the snapshot represents a commitment to keep both copies. If refreservation is set, usedbyrefreservation must be increased to the full size of refreservation when taking a new snapshot, accounting for this commitment. If there is insufficient space available to the dataset for this increase, snapshot creation will be denied.

This property can also be referred to by its shortened column name, refreserv.

aclinherit=discard | noallow | restricted | passthrough | passthrough-x passthrough-mode-preserve

Controls how ACL entries are inherited when files and directories are created. A file system with an aclinherit property of discard does not inherit any ACL entries. A file system with an aclinherit property value of noallow only inherits inheritable ACL entries that specify “deny” permissions. The property value restricted (the default) removes the write_acl and write_owner permissions when the ACL entry is inherited. A file system with an aclinherit property value of passthrough inherits all inheritable ACL entries without any modifications made to the ACL entries when they are inherited. A file system with an aclinherit property value of passthrough-x has the same meaning as passthrough, except that all ACEs inherit the execute permission only if the file creation mode also requests the execute bit. A file system with aclinherit property value of passthrough-mode-preserve has the same semantics as "passthrough" except that the owner@, group@, and everyone@ ACEs are overridden with values from the mode requested by the application when creating files and directories.

When the property value is set to passthrough, files are created with a mode determined by the inheritable ACEs. If no inheritable ACEs exist that affect the mode, then the mode is set in accordance to the requested mode from the application.

atime=on | off

Controls whether the access time for files is updated when they are read. Turning this property off avoids producing write traffic when reading files and can result in significant performance gains, though it might confuse mailers and other similar utilities. The default value is on.

canmount=on | off | noauto

If this property is set to off, the file system cannot be mounted, and is ignored by zfs mount -a. Setting this property to off is similar to setting the mountpoint property to none, except that the dataset still has a normal mountpoint property, which can be inherited. Setting this property to off allows datasets to be used solely as a mechanism to inherit properties. One example of setting canmount=off is to have two datasets with the same mountpoint, so that the children of both datasets appear in the same directory, but might have different inherited characteristics.

When the noauto option is set, a dataset can only be mounted and unmounted explicitly. The dataset is not mounted automatically when the dataset is created or imported, nor is it mounted by the zfs mount -a command or unmounted by the zfs unmount -a command.

This property is not inherited.

checksum=on | off | fletcher2,| fletcher4 | sha256 | sha256+mac

Controls the checksum used to verify data integrity. The default value is on, which automatically selects an appropriate algorithm (currently, fletcher4, but this may change in future releases). The value off disables integrity checking on user data. Disabling checksums is NOT a recommended practice.

Changing this property affects only newly-written data.

The value of sha256+mac is only available when encryption is enabled. The checksum property becomes readonly when encryption is enabled, and then is always set to sha256+mac.

compression=on | off | lzjb | gzip | gzip-N | zle | lz4

Controls the compression algorithm used for this dataset. The lzjb compression algorithm is optimized for performance while providing decent data compression. Setting compression to on uses the lzjb compression algorithm. The gzip compression algorithm uses the same compression as the gzip (1) command. You can specify the gzip level by using the value gzip-N where N is an integer from 1 (fastest) to 9 (best compression ratio). Currently, gzip is equivalent to gzip-6 (which is also the default for gzip (1) ). lz4 provides better compression than lzjb with lower CPU overhead.

This property can also be referred to by its shortened column name compress. Changing this property affects only newly-written data.

copies=1 | 2 | 3

Controls the number of copies of data stored for this dataset. These copies are in addition to any redundancy provided by the pool, for example, mirroring or RAID-Z. The copies are stored on different disks, if possible. The space used by multiple copies is charged to the associated file and dataset, changing the used property and counting against quotas and reservations.

Changing this property only affects newly-written data. Therefore, set this property at file system creation time by using the -o copies=N option.

When encryption is enabled on a dataset, copies can be set to a maximum of 2.

When the dataset is an auto-provisioned ZFS volume, change of the copies induces change to the refreservation as well. See the "refreservation" for details.

dedup=on | off | verify | sha256[,verify]

Controls whether deduplication is in effect for a dataset. The default value is off. The default checksum used for deduplication is sha256 (subject to change). When dedup is enabled, the dedup checksum algorithm overrides the checksum property. Setting the value to verify is equivalent to specifying sha256,verify.

If the property is set to verify, then, whenever two blocks have the same signature, ZFS will do a byte-for-byte comparison with the existing block to ensure that the contents are identical.

devices=on | off

Controls whether device nodes can be opened on this file system. The default value is on.

exec=on | off

Controls whether processes can be executed from within this file system. The default value is on.

logbias = latency | throughput

Controls how ZFS optimizes synchronous requests for this dataset. If logbias is set to latency, ZFS uses the pool's separate log devices, if any, to handle the requests at low latency. If logbias is set to throughput, ZFS does not use the pool's separate log devices. Instead, ZFS optimizes synchronous operations for global pool throughput and efficient use of resources. The default value is latency.

mlslabel=label | none

See the multilevel property for a description of the behavior of the mlslabel property on multilevel file systems. The following mlslabel description applies to non-multilevel file systems:

The mlslabel property is a sensitivity label that determines if a dataset can be mounted in a zone on a system with Trusted Extensions enabled. If the labeled dataset matches the labeled zone, the dataset can be mounted and accessed from the labeled zone.

When the mlslabel property is not set, the default value is none. Setting the mlslabel property to none is equivalent to removing the property.

The mlslabel property can be modified only when Trusted Extensions is enabled and only with appropriate privilege. Rights to modify it cannot be delegated. When changing a label to a higher label or setting the initial dataset label, the {PRIV_FILE_UPGRADE_SL} privilege is required. When changing a label to a lower label or the default (none), the {PRIV_FILE_DOWNGRADE_SL} privilege is required. Changing the dataset to labels other than the default can be done only when the dataset is not mounted. When a dataset with the default label is mounted into a labeled-zone, the mount operation automatically sets the mlslabel property to the label of that zone.

When Trusted Extensions is not enabled, only datasets with the default label (none) can be mounted.

mountpoint=path | none | legacy

Controls the mount point used for this file system. See the “Mount Points” section for more information on how this property is used.

When the mountpoint property is changed for a file system, the file system and any children that inherit the mount point are unmounted. If the new value is legacy, then they remain unmounted. Otherwise, they are automatically remounted in the new location if the property was previously legacy or none, or if they were mounted before the property was changed. In addition, any shared file systems are unshared and shared in the new location.

nbmand=on | off

For more information, see zfs_share(8).

primarycache=all | none | metadata

Controls what is cached in the primary cache (ARC). If this property is set to all, then both user data and metadata is cached. If this property is set to none, then neither user data nor metadata is cached. If this property is set to metadata, then only metadata is cached. The default value is all.

quota=size | none

Limits the amount of space a dataset and its descendents can consume. This includes all space consumed by descendents, including file systems and snapshots. Enforcement of quotas may be delayed by several seconds. This delay means that a user might exceed their quota before the system notices that the user is over quota. The system would then begin to refuse additional writes. Setting a quota on a descendent of a dataset that already has a quota does not override the ancestor's quota, but rather imposes an additional limit. Quotas cannot be set on volumes, as the volsize property acts as an implicit quota.

readlimit=size | none | default
writelimit=size | none | default

Limits the rate in bytes/second at which a dataset will be read or written to. A limit imposed on a dataset will apply to that dataset and all of its descendents. A value of 'none' overrides any default set by a parent. A value of 'default' will return the dataset to any default that was set by a parent. These values are not a guaranteed bandwidth and the actual bandwidth can be limited by other factors, including usage and limits set on other datasets in the hierarchy. Enforcement of these limits may be delayed by several seconds.

defaultreadlimit=size | none
defaultwritelimit=size | none

Sets a default limit for a dataset in bytes per second at which a dataset will be read or written to. A default limit imposed on a dataset will only apply to the datasets descendants. This value is inherited by the descendants and can be overridden by setting the readlimit or writelimit value on the descendent. These values are not a guaranteed bandwidth and the actual bandwidth can be limited by other factors including usage and limits set on other datasets in the hierarchy. Enforcement of these limits may be delayed by several seconds.

sync=standard | always | disabled

Determines the degree to which file system transactions are synchronized. This property can be set when a dataset is created, or dynamically, and will take effect immediately. This property can have one of the following settings:

standard

The default option. Synchronous file system transactions are written to the intent log and then all devices written are flushed to ensure the data is stable (that is, not cached by device controllers).

always

Each file system transaction is written and flushed to stable storage. This value has a significant performance penalty but might be appropriate for troubleshooting synchronous file system transactions.

disabled

Synchronous requests are disabled. File system transactions commit to stable storage only on the next DMU transaction group commit, which might be after many seconds. This setting gives the highest performance. However, it is very dangerous as ZFS would be ignoring the synchronous transaction demands of applications such as databases or NFS. Furthermore, when this setting is in effect for the currently active root or /var filesystem, out-of-spec behavior, application data loss, and increased vulnerability to replay attacks can result. Administrators should only use this option only when these risks are understood.

defaultuserquota=size | none

Sets the default user quota. The default value is none. This value will apply to all users who do not have an explicit userquota specified.

defaultgroupquota=size | none

Sets the default group quota. The default value is none. This value will apply to all groups who do not have an explicit userquota specified.

userquota@user=size | none | default

Limits the amount of space consumed by the specified user. Similar to the refquota property, the userquota space calculation does not include space that is used by descendent datasets, such as snapshots and clones. User space consumption is identified by the userspace@user property.

Enforcement of user quotas may be delayed by several seconds. This delay means that a user might exceed her quota before the system notices that she is over quota. The system would then begin to refuse additional writes with the EDQUOT error message . See the zfs userspace subcommand for more information.

Unprivileged users can only access their own groups' space usage. The root user, or a user who has been granted the userquota privilege with zfs allow, can get and set everyone's quota.

This property is not available on volumes, on file systems before version 4, or on pools before version 15. The userquota@... properties are not displayed by zfs get all. The user's name must be appended after the @ symbol, using one of the following forms:

  • POSIX name (for example, joe)

  • POSIX numeric ID (for example, 789)

  • SID name (for example, joe.smith@mydomain )

  • SID numeric ID (for example, S-1-123-456-789)

A value of default resets the quota to the default value defined by the defaultuserquota property.

groupquota@group= size | none | default

Limits the amount of space consumed by the specified group. Group space consumption is identified by the userquota@ user property.

Unprivileged users can access only their own groups' space usage. The root user, or a user who has been granted the groupquota privilege with zfs allow, can get and set all groups' quotas.

A value of default resets the groupquota to the default value defined by the defaultgroupquota property.

readonly=on | off

Controls whether this dataset can be modified. The default value is off.

This property can also be referred to by its shortened column name, rdonly.

recordsize=size

Specifies a suggested block size for files in the file system. This property is designed solely for use with database workloads that access files in fixed-size records. ZFS automatically tunes block sizes according to internal algorithms optimized for typical access patterns.

For databases that create very large files but access them in small random chunks, these algorithms may be suboptimal. Specifying a recordsize greater than or equal to the record size of the database can result in significant performance gains. Use of this property for general purpose file systems is strongly discouraged, and may adversely affect performance.

The default recordsize is 128 KB. The size specified must be a power of two greater than or equal to 512 and less than or equal to 1 MB.

Changing the file system's recordsize affects only files created afterward; existing files and received data are unaffected.

This property can also be referred to by its shortened column name, recsize.

refquota=size | none

Limits the amount of space a dataset can consume. This limit does not include space used by descendents, including file systems and snapshots. Enforcement of refquotas may be delayed by several seconds. This delay means that a user might exceed their quota before the system notices that the user is over quota. The system would then begin to refuse additional writes.

refreservation=size | none | auto

The minimum amount of space guaranteed to a dataset, not including its descendents.

The default refreservation is auto for ZFS volumes and none for other types of datasets. When refreservation=auto, sufficient space is reserved for the volume to store its designated volume size (volsize) and associated metadata. This effective reservation depends on both volsize and copies properties. A volume can also be manually provisioned by setting refreservation to a numeric value ( for example, zfs set refreservation=10g). Because of metadata, the actual space that is guaranteed for volume data will be slightly less than the requested numeric refreservation. A sparse volume (for example, when –s is specified at volume creation) is equivalent to one with a refreservation of none. Note that, refreservation=auto applies only to ZFS volumes.

Space that is reserved for a volume but that is not currently used by that volume is accounted for in usedbyrefreservation. Thus, the effective total refreservation for a zfs volume is always the sum of usedbydataset and usedbyrefreservation. This entire sum consumes from the parent datasets' usage, quotas, and reservations. This protects each dataset from overcommitment of pool resources, by ensuring that space for future writes is reserved in advance.

Space shared with snapshots can later be replaced with new data, and the snapshot represents a commitment to keep both copies. If refreservation is set, usedbyrefreservation must be increased to the full size of refreservation when taking a new snapshot, accounting for this commitment. If there is insufficient space available to the dataset for this increase, snapshot creation will be denied.

This property can also be referred to by its shortened column name, refreserv.

reservation=size | none

The minimum amount of space guaranteed to a dataset and its descendents. When the amount of space used is below this value, the dataset is treated as if it were taking up the amount of space specified by its reservation. Reservations are accounted for in the parent datasets' space used, and count against the parent datasets' quotas and reservations.

This property can also be referred to by its shortened column name, reserv.

rstchown=on | off

Indicates whether the file system restricts users from giving away their files by means of chown(1) or the chown(2) system call. The default is to restrict chown. When rstchown is off then chown will act as if the user has the PRIV_FILE_CHOWN_SELF privilege.

secondarycache=all | none | metadata

Controls what is cached in the secondary cache (L2ARC). If this property is set to all, then both user data and metadata is cached. If this property is set to none, then neither user data nor metadata is cached. If this property is set to metadata, then only metadata is cached. The default value is all.

setuid=on | off

Controls whether the set-UID bit is respected for the file system. The default value is on.

shadow=URI | none

Identifies a ZFS file system as a shadow of the file system described by the URI. Data is migrated to a shadow file system with this property set from the file system identified by the URI. The file system to be migrated must be read-only for a complete migration.

Access to a directory that is not yet migrated in the shadow file system is blocked until the entire directory is migrated. Access to a file that is not yet migrated in the shadow file system causes only a portion of the file being accessed to be migrated. Multiple processes can migrate different portions of a file at the same time.

Two forms of URI are accepted, one for migrating a local file system to another file system on the same physical system, and one for remotely migrating a file system from an NFS server. The forms are:

file:///path
nfs://host/path

If shadowd(8) is still running when the migration is complete, the file system is automatically remounted with the shadow property set to none. Or, when the migration is complete, you can manually set the shadow property to none.

sharenfs=on | off

For more information, see zfs_share(8).

sharesmb=on | off

For more information, see zfs_share(8).

snapdir=hidden | visible

Controls whether the .zfs directory is hidden or visible in the root of the file system as discussed in the “Snapshots” section. The default value is hidden.

version=1 | 2 | current

The on-disk version of this file system, which is independent of the pool version. This property can only be set to later supported versions. See the zfs upgrade command.

volsize=size

Specifies the logical size of the volume. By default, creating a volume establishes a refreservation that is a somewhat larger than the actual logical volume size, to account for ZFS metadata overhead. Any changes to volsize are reflected in an equivalent change to the refreservation. The volsize can only be set to a multiple of volblocksize, and cannot be zero.

The refreservation is set on the volume to prevent unexpected behavior for consumers. Without the reservation, the volume could run out of space, resulting in undefined behavior or data corruption, depending on how the volume is used. These effects can also occur when the volume size is changed while it is in use (particularly when shrinking the size). Extreme care should be used when adjusting the volume size. If the volume is auto-provisioned, change of its size also induces a change to the refreservation. For more information, see the "refreservation" section.

Though not recommended, a sparse volume (also known as thin provisioning) can be created by specifying the –s option to the zfs create -V command. A sparse volume is a volume where the reservation is less then the volume size. Consequently, writes to a sparse volume can fail with ENOSPC when the pool is low on space. For a sparse volume, changes to volsize are not reflected in the reservation.

vscan=on | off

For more information, see the zfs_share(8) man page.

xattr=on | off

Controls whether extended attributes are enabled for this file system. The default value is on.

zoned=on | off

Controls whether the dataset is managed from a non-global zone. See the “Zones” section for more information. The default value is off.

The following properties cannot be changed after the file system is created and, therefore, should be set when the file system is created. If the properties are not set with the zfs create or zpool create commands, these properties are inherited from the parent dataset. If the parent dataset lacks these properties due to having been created prior to these features being supported, the new file system will have the default values for these properties.

casesensitivity=sensitive | insensitive | mixed

For more information, see zfs_share(8).

normalization = none | formC | formD | formKC | formKD

For more information, see zfs_share(8).

utf8only=on | off

For more information, see zfs_share(8).

encryption=off | on | aes-128-ccm | aes-192-ccm | aes-256-ccm |
aes-128-gcm | aes-192-gcm | aes-256-gcm

For more information, see zfs_encrypt(8).

multilevel=on | off

The default value is off. It cannot be turned off after it set to on.

Objects in a multilevel file system are individually labeled with an explicit sensitivity label attribute that is automatically generated. Objects can be relabeled in place by changing this label attribute, by using the setlabel(1) or setflabel(3TSOL) interfaces.

Zone datasets, system root datasets, and other datasets containing packaged Solaris code should not be multilevel.

The upper bound of a multilevel file system is maintained in the mlslabel property. Normally the mlslabel is managed automatically by the system. It is set to ADMIN_LOW when the multilevel property is set on, and floats up to represent the maximum sensitivity label as files and directories are upgraded. After creating a multilevel file system, the mlslabel cannot be changed to a lower label, removed, or set to none.

When Trusted Extensions is enabled the mlslabel value defines the highest possible label that objects in the file system can have. Attempts to create a file at (or relabel a file to) a label higher than the mlslabel is not allowed. The mlslabel property can be set explicitly during file system creation, otherwise a default mlslabel property of ADMIN_HIGH will be automatically created. The mount policy based on mlslabel does not apply to multilevel file systems.

The following property must be specified at creation time and can modified by using special commands:

keysource=raw | hex | passphrase,prompt | file

For more information, see zfs_encrypt(8).

Temporary Mount Point Properties

When a file system is mounted, either through the legacy mount(8) command or the zfs mount command, its mount options are set according to its properties. The correlation between properties and mount options is as follows:

PROPERTY          MOUNT OPTION
     devices                 devices/nodevices
     mountpoint              mountpoint
     exec                    exec/noexec
     readonly                ro/rw
     setuid                  setuid/nosetuid
     xattr                   xattr/noxattr
     rstchown                rstchown/norstchown

In addition, these options can be set on a per-mount basis using the –o option, without affecting the property that is stored on disk. The values specified on the command line override the values stored in the dataset. The –nosuid option is an alias for nodevices,nosetuid. These properties are reported as temporary by the zfs get command. If the properties are changed while the dataset is mounted, the new setting overrides any temporary settings. If the property being modified is the mountpoint, the dataset will be immediately unmounted from the temporary mountpoint and remounted at the new persistent mountpoint.

User Properties

In addition to the standard native properties, ZFS supports arbitrary user properties. User properties have no effect on ZFS behavior, but applications or administrators can use them to annotate datasets (file systems, volumes, and snapshots).

User property names must contain a colon (:) character to distinguish them from native properties. They may contain lowercase letters, numbers, and the following punctuation characters: colon (:), dash (-), period (.), and underscore (_). The expected convention is that the property name is divided into two portions such as module: property, but this namespace is not enforced by ZFS. User property names can be at most 256 characters, and cannot begin with a dash (-).

When making programmatic use of user properties, it is strongly suggested to use a reversed DNS domain name for the module component of property names to reduce the chance that two independently-developed packages use the same property name for different purposes. In the Oracle Solaris release, the com.oracle user property is reserved for beadm command and library. The com.oracle:rootfs is reserved for Oracle Solaris boot. It defines the root filesystem dataset associated with a bootable dataset.

The values of user properties are arbitrary strings, are always inherited, and are never validated. All of the commands that operate on properties (zfs list, zfs get, zfs set, and so forth) can be used to manipulate both native properties and user properties. Use the zfs inherit command to clear a user property. If the property is not defined in any parent dataset, it is removed entirely. Property values are limited to 1024 characters.

ZFS Volumes as Swap or Dump Devices

During an initial installation, a swap device and dump device are created on ZFS volumes in the ZFS root pool. Separate ZFS volumes must be used for the swap area and dump devices. Do not swap to a file on a ZFS file system. A ZFS swap file configuration is not supported.

You can encrypt a ZFS volume used as a swap device by specifying the encryption property for that device and specifying the encrypted option in vfstab(5). For more information about the encryption property, see zfs_encrypt(8).

If you need to change your swap area or dump device after the system is installed or upgraded, use the swap(8) and dumpadm(8) commands. If you need to change the size of your swap area or dump device, see the Managing ZFS File Systems in Oracle Solaris 11.4 book.

SUBCOMMANDS

All subcommands that modify state are logged persistently to the pool in their original form.

zfs ?

Displays a help message.

zfs help command | help | property property-name | permission

Displays zfs command usage information. You can display help for a specific command, property, or delegated permission. If you display help for a specific command or property, the command syntax or property value is displayed. Using zfs help without any arguments displays a complete list of zfs commands.

zfs help –l properties

Displays zfs property information, including whether the property value is editable and inheritable, and their possible values.

zfs allow filesystem | volume
zfs allow [–ldug] everyone|user|group[,...] perm|@setname[,...] filesystem| volume
zfs allow [–ld] –e perm|@setname[,...] filesystem|volume
zfs allow –c perm|@setname[,...] filesystem|volume
zfs allow –s @setname perm|@setname[,...] filesystem|volume

For a full description of the zfs allow syntax and examples, see zfs_allow(8).

zfs clone [–p] [–K] [–o property=value] ... snapshot filesystem| volume

Creates a clone of the given snapshot. See the “Clones” section for details. The target dataset can be located anywhere in the ZFS hierarchy, and is created as the same type as the original.

–p

Creates all the non-existing parent datasets. Datasets created in this manner are automatically mounted according to the mountpoint property inherited from their parent. If the target file system or volume already exists, the operation completes successfully.

–o property= value

Sets the specified property; see zfs create for details.

–K

For information, see zfs_encrypt(8).

zfs create [-p] [–o property=value] ... filesystem

Creates a new ZFS file system. The file system is automatically mounted according to the mountpoint property inherited from the parent.

–p

Creates all the non-existing parent datasets. Datasets created in this manner are automatically mounted according to the mountpoint property inherited from their parent. Any property specified on the command line using the –o option is ignored. If the target filesystem already exists, the operation completes successfully.

–o property=value

Sets the specified property as if the command zfs set property=value was invoked at the same time the dataset was created. Any editable ZFS property can also be set at creation time. Multiple –o options can be specified. An error results if the same property is specified in multiple –o options.

zfs create [–ps] [–b blocksize] [–o property=value] ... –V size volume

Creates a volume of the given size. The volume is exported as a block device in /dev/zvol/{dsk,rdsk}/path, where path is the name of the volume in the ZFS namespace. The size represents the logical size as exported by the device. By default, a reservation of equal size is created.

size is automatically rounded up to the nearest 128 KB to ensure that the volume has an integral number of blocks regardless of blocksize.

–p

Creates all the non-existing parent datasets. Datasets created in this manner are automatically mounted according to the mountpoint property inherited from their parent. Any property specified on the command line using the –o option is ignored. If the target filesystem already exists, the operation completes successfully.

–s

Creates a sparse volume with no reservation. See volsize in the Native Properties section for more information about sparse volumes.

–o property= value

Sets the specified property as if the zfs set property=value command was invoked at the same time the dataset was created. Any editable ZFS property can also be set at creation time. Multiple –o options can be specified. An error results if the same property is specified in multiple –o options.

–b blocksize

Equivalent to –o volblocksize=blocksize. If this option is specified in conjunction with –o volblocksize, the resulting behavior is undefined.

zfs destroy [–rRsf] filesystem|volume

Destroys the given dataset and all of its snapshots. By default, the command unshares any file systems that are currently shared, unmounts any file systems that are currently mounted, and refuses to destroy a dataset that has active dependents (children or clones). The default behavior is to asynchronously reclaim the space occupied by the dataset after control returns to the caller. The progress of asynchronous dataset destroys can be seen by using the zpool monitor command. For more information, see the zpool(8) man page.

–r

Recursively destroy all children.

–R

Recursively destroy all dependents, including cloned file systems outside the target hierarchy.

–s

Destroys the snapshots synchronously. The default is to asynchronously reclaim destroyed datasets after the command returns to the caller. If this option is specified, control does not return to the caller until the blocks occupied by the datasets are fully freed.

–f

Force an unmount of any file systems using the unmount -f command. This option has no effect on non-file systems or unmounted file systems.

Extreme care should be taken when applying either the –r or the –f options, as they can destroy large portions of a pool and cause unexpected behavior for mounted file systems in use.

zfs destroy [–rRsd] snapshot

The given snapshot is destroyed immediately if and only if the zfs destroy command without the –d option would have destroyed it. Such immediate destruction would occur, for example, if the snapshot had no clones and the user-initiated reference count were zero.

If the snapshot does not qualify for immediate destruction, it is marked for deferred deletion. In this state, it exists as a usable, visible snapshot until both of the preconditions listed above are met, at which point it is destroyed.

–d

Defer snapshot deletion.

–r

Destroy (or mark for deferred deletion) all snapshots with this name in descendent file systems.

–R

Recursively destroy all dependents.

–s

Destroys the snapshots synchronously. The default is to asynchronously reclaim destroyed datasets after the command returns to the caller. If this option is specified, control does not return to the caller until the blocks occupied by the datasets are fully freed.

zfs destroy [share

The specified file system share is destroyed.

zfs diff [–FHNqrte] [–o field] ... snapshot [snapshot | filesystem]
zfs diff –E [–FHNqrt] [–o field] ... snapshot | filesystem

Gives a high-level description of the differences between a snapshot and a descendent dataset. The descendent can be either a snapshot of the dataset or the current dataset.

If a single snapshot is specified, then differences between that snapshot and the current dataset are given.

For each file that has undergone a change between the original snapshot and the descendent, the type of change is described along with the name of the file. In the case of a rename, both the old and new names are shown. Whitespace characters, backslash characters, and other non-printable or non-7-bit ASCII characters found in file names are displayed as a backslash character followed by the three-digit octal representation of the byte value.

If the –t option is specified, the first column of output from the command is the file's st_ctim value. For deleted files, this is the final st_ctim in the earlier snapshot.

The type of change follows any timestamp displayed, and is described with a single character:

+

Indicates the file was added in the later dataset.

-

Indicates the file was removed in the later dataset.

M

Indicates the file was modified in the later dataset.

R

Indicates the file was renamed in the later dataset.

If the –F option is specified, the next column of output is a single character describing the type of the file. The mappings are:

F

Regular file

/

Directory

B

Block device

>

Door

|

FIFO

@

Symbolic link

P

Event portal

=

Socket

If the modification involved a change in the link count of a non-directory file, the change is expressed as a delta within parentheses on the modification line. If the file was renamed, the old name is separated from the new with the string ->.

If the –H option is selected, easier-to-parse output is produced. Fields are separated by a single tab, and no arrow string (->) is placed between the old and new names of a rename. No guarantees are made on the spacing between fields of non –H output.

If the –e option is selected, then all files added or modified between the two snapshots are enumerated and no deleted files are displayed. The change type always reports as + regardless of the type of modification.

If the –E option is selected, then differences are given as if from an empty snapshot to the specified snapshot or dataset.

If the –r option is selected, the differences between the dataset and all the children datasets are displayed recursively. If a snapshot is given as a parameter, that snapshot name must exist for all the children datasets. Otherwise, warnings will be issued for datasets not containing the snapshot. If the –q option is also selected, these warnings will be silenced.

If the –N option is selected with –r, then all the new child datasets added to the current dataset will be enumerated, along with the differences among the existing datasets.

If the –o field option is selected then only selected fields are displayed. Each line starts with the standard fields requested by the –F and –t options, followed by the fields requested in successive –o options. As with the –H option, all fields are separated by a single tab. The allowable field names include:

object

The number printed by ls –i for the file

parent

The number printed by ls –i for enclosing directory of the file

size

The file size as displayed by ls –s

links

The number of links to the file

linkschange

The change in the number of links to the file

name

The name of the file

oldname

The name of the file before the rename, or (hyphen) if the file was not renamed

user

The owner name of the file as displayed by ls

group

The group name of the file as displayed by ls

ctime

Timestamp when the file's metadata was last modified

mtime

Timestamp when the file was last modified

atime

Timestamp when a file was last accessed

crtime

Timestamp when a file was created

mountpoint

Show the mountpoint name.

dataset_name

Show the dataset name.

You must be granted the diff permission with zfs allow to use this subcommand, unless you already have the {PRIV_SYS_CONFIG} or {PRIV_SYS_MOUNT} privilege.

zfs get [-rHpe| -d max] [–o all | field[,...] [–s source[,...]] all | property[,...] filesystem |volume|snapshot| share ...

Displays properties for the given datasets. If no datasets are specified, then the command displays properties for all datasets on the system. For each property, the following columns are displayed:

     name      Dataset name
     property  Property name
     value     Property value
     source    Property source. Can either be local, default,
               temporary, inherited, or none (-).

All columns except the RECEIVED column are displayed by default; specify particular or all columns, using the –o option. This command takes a comma-separated list of properties as described in the “Native Properties” and “User Properties” sections.

The special value all can be used to display all properties that apply to the given dataset's type (filesystem, volume, or snapshot).

–r

Recursively display properties for any children.

–H

Display output in a form more easily parsed by scripts. Any headers are omitted, and fields are explicitly separated by a single tab instead of an arbitrary amount of space.

–p

Displays numbers in parseable (exact) values.

–e

Expands property sublists to any depth.

–d max

Recursively displays any children of the dataset, limiting the recursion to depth. A depth of 1 will display only the dataset and its direct children.

–o field

Set of fields to display. One or more of:

name,property,value,received,source

Present multiple fields as a comma-separated list. The default value is:

name,property,value,source

The keyword all specifies all sources.

–s source

A comma-separated list of sources to display. Those properties coming from a source other than those in this list are ignored. Each source must be one of the following:

local,default,inherited,temporary,received,none

The default value is all sources.

zfs groupspace [–hniHp] [–o field[,...]] [–sS field]... [–t type [,...]] filesystem | snapshot

Displays space consumed by, and quotas on, each group in the specified filesystem or snapshot. This subcommand is identical to zfs userspace, except that the default types to display are –t posixgroup,smbgroup.

-
zfs hold [–r] tag snapshot ...

Adds a single reference, named with the tag argument, to the specified snapshot or snapshots. Each snapshot has its own tag namespace, and tags must be unique within that space.

If a hold exists on a snapshot, attempts to destroy that snapshot by using the zfs destroy command return EBUSY.

–r

Specifies that a hold with the given tag is applied recursively to the snapshots of all descendent file systems.

zfs holds [–r] snapshot ...

Lists all existing user references for the given snapshot or snapshots.

–r

Lists the holds that are set on the named descendent snapshots, in addition to listing the holds on the named snapshot.

zfs inherit [–rS] property filesystem|volume| snapshot|share ...

Clears the specified property, causing it to be inherited from an ancestor. If no ancestor has the property set, then the default value is used. See the “Properties” section for a listing of default values, and details on which properties can be inherited.

–r

Recursively inherits the given property for all children.

–S

Reverts to the received property value, if any. If the property does not have a received value, the behavior of zfs inherit –S is the same as zfs inherit without –S. If the property does have a received value, zfs inherit masks the received value with the inherited value until zfs inherit –S reverts to the received value.

zfs key –l | {–a | [–r] filesystem|volume}
zfs key –u [–f] | {–a | [–r] filesystem | volume
zfs key –c [–o keysource=value] {–a | [–r] filesystem| volume}
zfs key –K {–a | [–r] filesystem|volume}

For a full description of the zfs key syntax and examples, see zfs_encrypt(8).

zfs list [-rH| -d max] [-o property[,...]] [ -t type[,...]] [-I state,...][ -s property ] ... [ -S property ] ... [filesystem|volume| snapshot|share|path] ...

Lists the property information for the given datasets in tabular form. If specified, you can list property information by the absolute pathname or the relative pathname. By default, all file systems and volumes are displayed. Snapshots are displayed if the listsnaps property is on. The default is off. Shares are displayed if the listshares property is on. The following fields are displayed: name, used, available, referenced, mountpoint.

–H

Used for scripting mode. Do not print headers and separate fields by a single tab instead of arbitrary white space.

–r

Recursively displays any children of the dataset on the command line.

–d depth

Recursively displays any children of the dataset, limiting the recursion to maximum depth. A depth of 1 will display only the dataset and its direct children.

–o property

A comma-separated list of properties to display. The property must be:

  • One of the properties described in the “Native Properties” section

  • A user property

  • The value name to display the dataset name

  • The value space to display space usage properties on file systems and volumes. This is a shortcut for specifying –o name,avail,used,usedsnap,usedds,usedrefreserv,usedchild –t filesystem,volume syntax.

–s property

A property for sorting the output by column in ascending order based on the value of the property. The property must be one of the properties described in the “Properties” section, or the special value name to sort by the dataset name. Multiple properties can be specified at one time using multiple –s property options. Multiple –s options are evaluated from left to right in decreasing order of importance.

The following is a list of sorting criteria:

  • Numeric types sort in numeric order.

  • String types sort in alphabetical order.

  • Types inappropriate for a row sort that row to the literal bottom, regardless of the specified ordering.

  • If no sorting options are specified the existing behavior of zfs list is preserved.

–S property

Same as the –s option, but sorts by property in descending order.

–t type

A comma-separated list of types to display, where type is one of filesystem, snapshot, volume, share, or all. For example, specifying –t snapshot displays only snapshots. The following aliases can be used in place of the type specifiers: fs (filesystem), snap (snapshot), and vol (volume).

–I state

A comma-separated list of dataset states to display instead of the 'normal' datasets that are usually displayed. The state parameter can include the following non-normal states: receiving, resumable, hidden, or all. For instance, specifying –I resumable will display only resumable datasets. The state value 'all' will list all datasets in states other than the 'normal' state.

–p

Uses the exact (parseable) numeric output.

zfs mount

Displays all ZFS file systems currently mounted.

zfs mount [–vOS] [–o options] –a | filesystem

Mounts ZFS file systems. Invoked automatically as part of the boot process.

–o options

An optional, comma-separated list of mount options to use temporarily for the duration of the mount. See the “Temporary Mount Point Properties” section for details.

–O

Perform an overlay mount. See mount(8) for more information.

–v

Report mount progress.

–a

Mount all available ZFS file systems. Invoked automatically as part of the boot process.

filesystem

Mount the specified filesystem.

A zfs mount operation for an encrypted dataset might prompt you for a key, depending on the keysource property value. This might occur, for example, if the keysource locator is set to prompt.

zfs promote clone-filesystem

Promotes a clone file system to no longer be dependent on its origin snapshot. This makes it possible to destroy the file system that the clone was created from. The clone parent-child dependency relationship is reversed, so that the origin file system becomes a clone of the specified file system.

The snapshot that was cloned, and any snapshots previous to this snapshot, are now owned by the promoted clone. The space they use moves from the origin file system to the promoted clone, so enough space must be available to accommodate these snapshots. No new space is consumed by this operation, but the space accounting is adjusted. The promoted clone must not have any conflicting snapshot names of its own. The rename subcommand can be used to rename any conflicting snapshots.

zfs receive [–vnFu] [[–o property=value] | [–x property]] ... filesystem |volume|snapshot
zfs receive [–vnFu] [[–o property=value] | [–x property]] ... [–d | –e] filesystem
zfs receive –C <filesystem|volume>

Creates a snapshot whose contents are as specified in the stream provided on standard input. If a full stream is received, then a new file system is created as well. Streams are created using the zfs send subcommand, which by default creates a full stream. zfs recv can be used as an alias for zfs receive.

If an incremental stream is received, then the destination file system must already exist, and its most recent snapshot must match the incremental stream's source. For ZFS volumes, the destination device link is destroyed and recreated, which means the volume cannot be accessed during the receive operation.

When a snapshot replication package stream that is generated by using the zfs send –R command is received, any snapshots that do not exist on the sending location are destroyed by using the zfs destroy –d command. If –o property=value or –x property is specified, it applies to the effective value of the property throughout the entire subtree of replicated datasets. Effective property values may be set or inherited, depending on the property and whether the dataset is the topmost in the replicated subtree. Received properties are retained in spite of being overridden and may be restored with zfs inherit –rS or zfs send –Rb.

The name of the snapshot (and file system, if a full stream is received) that this subcommand creates depends on the argument type and the –d or –e option.

If the argument is a snapshot name, the specified snapshot is created. If the argument is a file system or volume name, a snapshot with the same name as the sent snapshot is created within the specified filesystem or volume. If the –d or –e option is specified, the snapshot name is determined by appending the sent snapshot's name to the specified filesystem. If the –d option is specified, all but the pool name of the sent snapshot path is appended (for example, b/c@1 appended from sent snapshot a/b/c@1), and if the –e option is specified, only the tail of the sent snapshot path is appended (for example, c@1 appended from sent snapshot a/b/c@1). In the case of –d, any file systems needed to replicate the path of the sent snapshot are created within the specified file system.

–d

Uses all but the first element of the sent snapshot path (all but the pool name) to determine the name of the new snapshot as described in the paragraph above.

–C

Write a receive checkpoint to stdout. A receive checkpoint is a table of contents of snapshots already received.

–e

Uses the last element of the sent snapshot path to determine the name of the new snapshot as described in the paragraph above.

–F

Forces a rollback of the file system to the most recent snapshot before performing the receive operation. If receiving an incremental replication stream (for example, one generated by zfs send -R -[iI]), destroy snapshots and file systems that do not exist on the sending side.

–n

Do not actually receive the stream. This can be useful in conjunction with the –v option to verify the name the receive operation would use.

Note that ZFS does not verify whether the file systems and clones required by the stream exists. Therefore, actual receive can fail due to unfulfilled stream dependencies even though the simulated receive passed.

–o property=value

Sets the specified property as if the command zfs set property=value is invoked at the same time the received dataset is created from the non-incremental send stream or updated from the incremental send stream. Any editable ZFS property can also be set at receive time. Set-once properties bound to the received data, such as normalization and casesensitivity, cannot be set at receive time even when the datasets are newly created by zfs receive. Multiple –o options can be specified. An error results if the same property is specified in multiple -o or –x options.

–u

File system that is associated with the received stream is not mounted.

–v

Print verbose information about the stream and the time required to perform the receive operation.

–x property

Ensures that the effective value of the specified property after the receive is unaffected by the value of that property in the send stream (if any), as if the property had been excluded from the send stream. If the specified property is not present in the send stream, this option does nothing. If a received property needs to be overridden, the effective value can be set or inherited, depending on the property. In the case of an incremental update, –x leaves any existing local setting or explicit inheritance unchanged (since the received property is already overridden). All –o restrictions apply equally to –x.

zfs release [–r] tag snapshot...

Removes a single reference, named with the tag argument, from the specified snapshot or snapshots. The tag must already exist for each snapshot.

If a hold exists on a snapshot, attempts to destroy that snapshot by using the zfs destroy command return EBUSY.

–r

Recursively releases a hold with the given tag on the snapshots of all descendent file systems.

zfs rename filesystem|volume|snapshot
filesystem|volume|snapshot
zfs rename [-p] filesystem|volume filesystem|volume

Renames the given dataset. The new target can be located anywhere in the ZFS hierarchy, with the exception of snapshots. Snapshots can only be renamed within the parent file system or volume. When renaming a snapshot, the parent file system of the snapshot does not need to be specified as part of the second argument. Renamed file systems can inherit new mount points, in which case they are unmounted and remounted at the new mount point.

ZFS needs all child datasets to be unmounted before the parent ZFS dataset can be renamed. If the child dataset cannot be unmounted, zfs reports an error.

$ zfs rename rpool/parent rpool/renamed
cannot unmount '/rpool/child': Device busy

In such a situation, it is possible to rename the dataset with this approach:

$ zfs snapshot rpool/parent@rename
$ zfs clone rpool/parent@rename rpool/renamed
$ zfs promote rpool/renamed
$ zfs destroy rpool/parent
$ zfs destroy rpool/renamed@rename

Note that all data written to rpool/parent after creating the @rename snapshot will be lost.

Renaming root dataset is not allowed. The root dataset can only be renamed by renaming the pool, which will rename the root dataset to the new pool name. Use zpool export <pool> command and then zpool import <pool> <newpoolname> command to rename the root dataset to the new pool name.

–p

Creates all the non-existent parent datasets. Datasets created in this manner are automatically mounted according to the mountpoint property inherited from their parent.

zfs rename -r snapshot snapshot

Recursively renames the snapshots of all descendent datasets. Snapshots are the only dataset that can be renamed recursively.

zfs rename share share

Renames the specified share to a new share name.

zfs rollback [–rRf] snapshot

Rolls back the given dataset to a previous snapshot. When a dataset is rolled back, all data that has changed since the snapshot is discarded, and the dataset reverts to the state at the time of the snapshot. By default, the command refuses to roll back to a snapshot other than the most recent one. In order to do so, all intermediate snapshots must be destroyed by specifying the –r option.

The –rR options do not recursively destroy the child snapshots of a recursive snapshot. Only the top-level recursive snapshot is destroyed by either of these options. To completely roll back a recursive snapshot, you must rollback the individual child snapshots.

–r

Recursively destroys any snapshots more recent than the one specified.

–R

Recursively destroys any more recent snapshots, as well as any clones of those snapshots.

–f

Used with the –R option to force an unmount of any clone file systems that are to be destroyed.

zfs send [–vbpnC] [-[Rr[c]]] [–w compress|none] [-D [-m <memsize>]]
[-[iI] <snapshot>] [-s <subopt>] <snapshot>

Creates a stream representation of the second snapshot , which is written to standard output. The output can be redirected to a file or to a different system (for example, using ssh(1). By default, a full stream is generated.

–b

Sends only received property values whether or not they are overridden by local settings, but only if the dataset has ever been received. Use this option when you want zfs receive to restore received properties backed up on the sent dataset and to avoid sending local settings that may have nothing to do with the source dataset, but only with how the data is backed up.

–c

Creates a self-contained stream. A self-contained stream is one that is not dependent on any datasets not included in the stream package. Valid with the –r and –R options. If used with the –R option and if clones are present, no snapshot preceding the clone origin will be included in the stream. If used with the –i or –I option, the stream will be dependent on the snapshot specified as an argument to the –i or –I option.

See the "ZFS Streams" section of the ZFS Administration Guide for details.

–C

Read a receive checkpoint from stdin. A receive checkpoint is a table of contents of snapshots that have been successfully received and do not need to be sent again.

–D

Performs dedup processing on the stream. Deduplicated streams cannot be received on systems that do not support the stream deduplication feature.

See the “ZFS Streams” section of the ZFS Administration Guide to understand how a replication stream package differs from a recursive stream package.

–i snapshot

Generates an incremental stream from the first snapshot to the second snapshot. The incremental source (the first snapshot) can be specified as the last component of the snapshot name (for example, the part after the @), and it is assumed to be from the same file system as the second snapshot.

If the destination is a clone, the source may be the origin snapshot, which must be fully specified (for example, pool/fs@origin, not just @origin).

–I snapshot

Generates a stream package that sends all intermediary snapshots from the first snapshot to the second snapshot. For example, -I @a fs@d is similar to -i @a fs@b; -i @b fs@c; -i @c fs@d. The incremental source snapshot may be specified as with the -i option.

–n

Do not actually send the stream. This option can also be used with the –v option to see what snapshots would have been sent.

–p

Use the –p option to include properties in the send stream without the –R option. For more information, see Applying Different Property Values to a ZFS Snapshot Stream in Managing ZFS File Systems in Oracle Solaris 11.4

–R

Generates a replication stream package that replicates the specified file system, and all descendent file systems, up to the named snapshot. When received, all properties, snapshots, descendent file systems, and clones are preserved.

If the -i or -I flags are used in conjunction with the -R flag, an incremental replication stream is generated. The current values of properties, and current snapshot and file system names are set when the stream is received. If the -F flag is specified when this stream is received, snapshots and file systems that do not exist on the sending side are destroyed.

When combined with the –c option, a self-contained replication stream package is created. If clones are present, no snapshot preceding the clone origin will be included in the stream. If both the –c and –I options are used, file systems and volumes that do not have the snapshot specified with the –I option are sent as self-contained streams.

–r

Generates a recursive stream package. A recursive stream package contains a series of full and/or incremental streams. When received, all properties and descendent file systems are preserved. Unlike with the replication stream packages generated with the –R flag, intermediate snapshots are not preserved unless the intermediate snapshot is the origin of a clone that is included in the stream.

If the –i option is used in conjunction with the –r option, an incremental recursive stream is generated. The current values of properties as well as current snapshot and file system names are set when the stream is received. If the –F option is specified when this stream is received, snapshots and file systems that do not exist on the sending side are destroyed. The –I option cannot be used in conjunction with the –r option.

When combined with the –c option, a self-contained recursive stream package is created. If both the –c and –i options are used, file systems and volumes that do not have the snapshot specified with the –i option are sent as self-contained streams.

See the “ZFS Streams” section of the ZFS Administration Guide to understand how a recursive stream package differs from a replication stream package.

–s streamsize

The –s switch is used to specify a set of stream options that modify the format of the stream or the operation of the send command. Later options take precedence over earlier options. Any option can be preceded by 'no' to turn the option off. For example –s nocheck requests the use of a stream format without per-record checksums.

Specifies that the size of the stream, in bytes, that will be output to stderr. –v suppresses the –s streamsize option.

–s check

Specifies that the output stream will use a send stream format that uses per-record checksums. This format is the system-wide default. When an interrupted transfer is resumed by using a receive checkpoint (see zfs send –-C), the use of the 'check' format before the outage enables the resumed transfer to preserve and reuse the portions of the interrupted snapshot that were already successfully received.

–s nocheck

Specifies that the output stream will use a legacy send stream format without per-record checksums. This format is suitable for transmission to older systems that do not support the new format.

–v

Displays verbose information about the stream package generated.

–w

Specifies the compress argument. The compressed filesystem blocks are sent compressed in the stream, that is, without decompressing them. compress also implicitly enables the –p option, and is mutually exclusive with the –D option.

The none argument disables the compress behaviour. none is the default argument, when the –w option is not specified.

–m <memsize>

Limits the amount of memory used by deduplication processing to the value specified in bytes, kbytes, mbytes, or gbytes by using the appropriate suffix. For example, 2G, 2048M, 2097152K, or 2147483648.

–s memsize

Specifies that the deduplication memory size, in bytes, will be output to stderr. If both –s streamsize and –s memsize options are specified, the values are output on successive lines in the order specified on the command line. –s option is incompatible with –v option.

The format of the stream is committed. You will be able to receive your streams on future versions of ZFS.

The snapshot specified by the snapshot argument must exist. If the –R or –r options are used then a recursive snapshot as specified by the snapshot argument should exist and will be sent recursively. There are two special cases. First, a descendant filesystem tree that is completely missing the appropriate named snapshot will be skipped and will not be included in the send stream. In this case, a warning message will be printed for each snapshot that is skipped. Second, if a descendant filesystem tree is of mixed status (that is, the root of the descendant filesystem tree is missing the requested snapshot but one or more of its child filesystems do have the requested snapshot), then an error is generated to terminate the send operation.

To send snapshots of multilevel filesystems, the user's process clearance must dominate the label specified by the mlslabel property.

zfs set [–r] property=value filesystem|volume|snapshot ...

Sets the property to the given value for each dataset. Only some properties can be edited. See the “Properties” section for more information on what properties can be set and acceptable values. Numeric values can be specified as exact values, or in a human-readable form with a suffix of B, K, M, G, T, P, E, Z (for bytes, kilobytes, megabytes, gigabytes, terabytes, petabytes, exabytes, or zettabytes, respectively). User properties can be set on snapshots. For more information, see the “User Properties” section.

–r

Recursively apply the effective value of the setting throughout the subtree of child datasets. The effective value may be set or inherited, depending on the property. Use the zfs help –l properties command to review whether a property is settable or inheritable.

zfs share [–u] –o property=value ... filesystem%share
zfs share filesystem|mountpoint|filesystem%share
zfs share –a | filesystem

For a full description of zfs share syntax and examples and setting the share.nfs or share.smb property, see zfs_share(8).

zfs snapshot [–r] [–o property=value] ... filesystem@snapname|volume@snapname

Creates a snapshot with the given name. All previous modifications by successful system calls to the file system are part of the snapshot. zfs snap can be used as an alias for zfs snapshot. See the “Snapshots” section for details.

–r

Recursively creates snapshots of all descendent datasets. Snapshots are taken atomically, so that all recursive snapshots correspond to the same moment in time.

–o property=value

Sets the specified property; see zfs create for details.

zfs unallow [–rldug] everyone|user|group[,...] [perm|@setname[, ...]] filesystem|volume
zfs unallow [–rld] –e [perm|@setname [,...]] filesystem|volume
zfs unallow [–r] –c [perm|@setname[,...]]
filesystem|volume
zfs unallow [–r] –s @setname [perm|@setname[,...]]
filesystem|volume

For a full description of the zfs unallow syntax and examples, see zfs_allow(8).

zfs unmount [–f] –a | filesystem|mountpoint

Unmounts currently mounted ZFS file systems. Invoked automatically as part of the shutdown process.

–f

Forcefully unmount the file system, even if it is currently in use.

–a

Unmounts all available ZFS file systems. Invoked automatically as part of the boot process.

filesystem|mountpoint

Unmounts the specified filesystem. The command can also be given a path to a ZFS file system mount point on the system.

For an encrypted dataset, the key is not unloaded when the file system is unmounted. To unload the key, see zfs key.

zfs unshare filesystem| mountpoint|filesystem%share
zfs unshare –a | –r filesystem

For a full description of zfs unshare syntax and examples, see zfs_share(8).

zfs upgrade

Identifies a file system version, which determines available file system features in the currently running software release. You can continue to use older file system versions, but some features might not be available. A file system can be upgraded by using the zfs upgrade –a command. You will not be able to access a file system of a later version on a system that runs an earlier software version.

zfs upgrade [–v]

Displays ZFS file system versions that are supported by the current software. The current ZFS file system versions and all previously supported versions are displayed, along with an explanation of the features provided with each version.

zfs upgrade [–r] [–V version] [–a | filesystem]

Upgrades file systems to a new, on-disk version. Upgrading a file system means that it will no longer be accessible on a system running an older software version. A zfs send stream that is generated from a new file system snapshot cannot be accessed on a system that runs an older software version.

In general, the file system version is independent of the pool version. See zpool(8) for information on the zpool upgrade command.

In some cases, the file system version and the pool version are interrelated and the pool version must be upgraded before the file system version can be upgraded.

–a

Upgrades all file systems on all imported pools.

filesystem

Upgrades the specified file system.

–r

Upgrades the specified file system and all descendent file systems.

–V version

Upgrades to the specified version. If the –V flag is not specified, this command upgrades to the most recent version. This option can only be used to increase the version number, and only up to the most recent version supported by this software.

zfs userspace [–hniHp] [–o field[,...]] [–sS field]... [–t type [,...]] filesystem | snapshot

Displays space consumed by, and quotas on, each user in the specified filesystem or snapshot. This corresponds to the userused@ user and userquota@user properties.

–h

Displays syntax help message and exit.

–n

Prints numeric ID instead of user/group name.

–H

Does not print headers, use tab-delimited output.

–p

Uses exact (parseable) numeric output.

–o field[,...]

Displays only the specified fields from the following set, type,name,used,quota. The default is to display all fields.

–s field

Sorts output by this field. The s and S flags may be specified multiple times to sort first by one field, then by another. The default is –s type –s name.

–S field

Sorts by this field in reverse order. See –s.

–t type[,...]

Prints only the specified types from the following set, all,posixuser,smbuser,posixgroup,smbgroup.

The default is –t posixuser,smbuser

The default can be changed to include group types.

–i

Translates SID to POSIX ID. The POSIX ID may be ephemeral if no mapping exists. Normal POSIX interfaces (for example, stat(2), ls –l) perform this translation, so the –i option allows the output from zfs userspace to be compared directly with those utilities. However, –i may lead to confusion if some files were created by an SMB user before a SMB-to-POSIX name mapping was established. In such a case, some files are owned by the SMB entity and some by the POSIX entity. However, the –i option will report that the POSIX entity has the total usage and quota for both.

Examples

Example 1 Creating a ZFS File System Hierarchy

The following commands create a file system named pool/home and a file system named pool/home/bob. The mount point /export/home is set for the parent file system, and is automatically inherited by the child file system.

# zfs create pool/home
# zfs set mountpoint=/export/home pool/home
# zfs create pool/home/bob
Example 2 Creating a ZFS Snapshot

The following command creates a snapshot named yesterday. This snapshot is mounted on demand in the .zfs/snapshot directory at the root of the pool/home/bob file system.

# zfs snapshot pool/home/bob@yesterday
Example 3 Creating and Destroying Multiple Snapshots

The following command creates snapshots named yesterday of pool/home and all of its descendent file systems. Each snapshot is mounted on demand in the .zfs/snapshot directory at the root of its file system. The second command destroys the newly created snapshots.

# zfs snapshot -r pool/home@yesterday
# zfs destroy -r pool/home@yesterday
Example 4 Disabling and Enabling File System Compression

The following command disables the compression property for all file systems under pool/home. The next command explicitly enables compression for pool/home/anne.

# zfs set compression=off pool/home
# zfs set compression=on pool/home/anne
Example 5 Listing ZFS Datasets

The following command lists all active file systems and volumes in the system. Snapshots are displayed if the listsnaps property is on. The default is off. Shares are displayed if the listshares property is on. See zpool(8) for more information on pool properties.

# zfs list
   NAME                      USED  AVAIL  REFER  MOUNTPOINT
   pool                      450K   457G    18K  /pool
   pool/home                 315K   457G    21K  /export/home
   pool/home/anne             18K   457G    18K  /export/home/anne
   pool/home/bob             276K   457G   276K  /export/home/bob
Example 6 Setting a Quota on a ZFS File System

The following command sets a quota of 30 GB for pool/home/bob.

# zfs set quota=30G pool/home/bob
Example 7 Listing ZFS Properties

The following command lists all properties for pool/home/bob.

# zfs get all pool/home/bob
NAME           PROPERTY              VALUE                  SOURCE
pool/home/bob  aclinherit            restricted             default
pool/home/bob  aclmode               discard                default
pool/home/bob  atime                 on                     default
pool/home/bob  available             30.0G                  -
pool/home/bob  canmount              on                     default
pool/home/bob  casesensitivity       mixed                  -
pool/home/bob  checksum              on                     default
pool/home/bob  compression           on                     local
pool/home/bob  compressratio         1.00x                  -
pool/home/bob  copies                1                      default
pool/home/bob  creation              Tue Jul  3 10:39 2012  -
pool/home/bob  dedup                 off                    default
pool/home/bob  devices               on                     default
pool/home/bob  encryption            off                    -
pool/home/bob  exec                  on                     default
pool/home/bob  keychangedate         -                      default
pool/home/bob  keysource             none                   default
pool/home/bob  keystatus             none                   -
pool/home/bob  logbias               latency                default
pool/home/bob  mlslabel              none                   -
pool/home/bob  mounted               yes                    -
pool/home/bob  mountpoint            /pool/home/bob         default
pool/home/bob  multilevel            off                    -
pool/home/bob  nbmand                off                    default
pool/home/bob  normalization         none                   -
pool/home/bob  primarycache          all                    default
pool/home/bob  quota                 30G                    local
pool/home/bob  readonly              off                    default
pool/home/bob  recordsize            128K                   default
pool/home/bob  referenced            31K                    -
pool/home/bob  refquota              none                   default
pool/home/bob  refreservation        none                   default
pool/home/bob  rekeydate             -                      default
pool/home/bob  reservation           none                   default
pool/home/bob  rstchown              on                     default
pool/home/bob  secondarycache        all                    default
pool/home/bob  setuid                on                     default
pool/home/bob  shadow                none                   -
pool/home/bob  share.*               ...                    inherited
pool/home/bob  snapdir               hidden                 default
pool/home/bob  sync                  standard               default
pool/home/bob  type                  filesystem             -
pool/home/bob  used                  31K                    -
pool/home/bob  usedbychildren        0                      -
pool/home/bob  usedbydataset         31K                    -
pool/home/bob  usedbyrefreservation  0                      -
pool/home/bob  usedbysnapshots       0                      -
pool/home/bob  utf8only              off                    -
pool/home/bob  version               6                      -
pool/home/bob  vscan                 off                    default
pool/home/bob  xattr                 on                     default
pool/home/bob  zoned                 off                    default

The following command gets a single property value.

# zfs get -H -o value compression pool/home/bob
on

The following command lists all properties with local settings for pool/home/bob.

# zfs get -r -s local -o name,property,value all pool/home/bob

NAME            PROPERTY  VALUE
pool/home/bob   compression  on
pool/home/bob   quota     30G
Example 8 Rolling Back a ZFS File System

The following command reverts the contents of pool/home/anne to the snapshot named yesterday, deleting all intermediate snapshots.

# zfs rollback -r pool/home/anne@yesterday
Example 9 Creating a ZFS Clone

The following command creates a writable file system whose initial contents are the same as pool/home/bob@yesterday.

# zfs clone pool/home/bob@yesterday pool/clone
Example 10 Promoting a ZFS Clone

The following commands illustrate how to test out changes to a file system, and then replace the original file system with the changed one, using clones, clone promotion, and renaming:

# zfs create pool/project/production
  populate /pool/project/production with data
# zfs snapshot pool/project/production@today
# zfs clone pool/project/production@today pool/project/beta
make changes to /pool/project/beta and test them
# zfs promote pool/project/beta
# zfs rename pool/project/production pool/project/legacy
# zfs rename pool/project/beta pool/project/production
once the legacy version is no longer needed, it can be destroyed
# zfs destroy pool/project/legacy
Example 11 Inheriting ZFS Properties

The following command causes pool/home/bob and pool/home/anne to inherit the checksum property from their parent.

# zfs inherit checksum pool/home/bob pool/home/anne
Example 12 Remotely Replicating ZFS Data

The following commands send a full stream and then an incremental stream to a remote machine, restoring them into poolB/received/fs@aand poolB/received/fs@b, respectively. poolB must contain the file system poolB/received, and must not initially contain poolB/received/fs.

# zfs send pool/fs@a | \
   ssh host zfs receive poolB/received/fs@a
# zfs send -i a pool/fs@b | ssh host \
   zfs receive poolB/received/fs

The above syntax assumes that sshd has been configured to allow remote root access.

Example 13 Using the zfs receive –d Option

The following command sends a full stream of poolA/fsA/fsB@snap to a remote machine, receiving it into poolB/received/fsA/fsB@snap. The fsA/fsB@snap portion of the received snapshot's name is determined from the name of the sent snapshot. poolB must contain the file system poolB/received. If poolB/received/fsA does not exist, it is created as an empty file system.

# zfs send poolA/fsA/fsB@snap | \
   ssh host zfs receive -d poolB/received
Example 14 Setting User Properties

The following example sets the user–defined com.example:department property for a dataset.

# zfs set com.example:department=12345 tank/accounting
Example 15 Performing a Rolling Snapshot

The following example shows how to maintain a history of snapshots with a consistent naming scheme. To keep a week's worth of snapshots, the user destroys the oldest snapshot, renames the remaining snapshots, and then creates a new snapshot, as follows:

# zfs destroy -r pool/users@7daysago
# zfs rename -r pool/users@6daysago @7daysago
# zfs rename -r pool/users@5daysago @6daysago
# zfs rename -r pool/users@4daysago @5daysago
# zfs rename -r pool/users@3daysago @4daysago
# zfs rename -r pool/users@2daysago @3daysago
# zfs rename -r pool/users@yesterday @2daysago
# zfs rename -r pool/users@today @yesterday
# zfs snapshot -r pool/users@today
Example 16 Displaying ZFS Snapshot Differences

The following example is output of the zfs diff –F and –t options specified:

# zfs diff -Ft myfiles@snap1
1269962501.206726811   M   /   /myfiles/
1269962444.207369955   M   F   /myfiles/link_to_me      (+1)
1269962499.207519034   R       /myfiles/rename_me -> /myfiles/renamed
1269962431.813566720   -   F   /myfiles/delete_me
1269962518.666905544   +   F   /myfiles/new_file
1269962501.393099817   +   |   /myfiles/new_pipe
Example 17 Resuming an Interrupted Send/Receive

Request that the dataset hierarchy at dst/fs on system target be made to match the source hierarchy src/fs as of the recursive snapshot @TOSNAP:

# zfs send -R src/fs@TOSNAP | \
   ssh target zfs receive -F dst/fs

If the above command is interrupted, request the transfer be resumed where it left off:

# ssh target zfs receive -C dst/fs | \
   zfs send -RC src@TOSNAP | \
   ssh target zfs receive -F dst/fs

Similarly, to request that a dataset hierarchy dst/fs on system target that already matches the source hierarchy as of recursive snapshot @FROMSNAP now be incrementally updated to match the new source recursive snapshot @TOSNAP:

# zfs send -R -I src/fs@FROMSNAP src/fs@TOSNAP | \
   ssh target zfs receive -F dst/fs

If the above incremental update is interrupted, request the transfer be resumed where it left off:

# ssh target zfs receive -C dst/fs | \
  zfs send -RC -I src/fs@FROMSNAP src/fs@TOSNAP | \
  ssh target zfs receive -F dst/fs
Example 18 Display Incomplete Datasets
# zfs list -I all tank/dest
   NAME                 USED  AVAIL  REFER  TYPE        STATE
   tank/dest/one/%now   521M   120G   521M  volume      receiving
   tank/dest/two       33.8M   120G  33.8M  filesystem  resumable
Example 19 Destroy Resumable Datasets

Resumable datasets that will never be resumed can be destroyed to release space. Care should be taken to make sure the correct datasets are listed and that the incompletely received data will never be resumed. Then the following command will remove the resumable datasets:

# zfs list -HI resumable -o name tank/dest | \
   xargs -i -n1 zfs destroy "{}"

Exit Status

The following exit values are returned:

0

Successful completion.

1

An error occurred.

2

Invalid command line options were specified.

3

A fatal error occurred.

Attributes

See attributes(7) for descriptions of the following attributes:

ATTRIBUTE TYPE
ATTRIBUTE VALUE
Availability
system/file-system/zfs
Interface Stability
Committed

See Also

chmod(1), chown(1), pktool(1), setlabel(1), ssh(1), chmod(2), chown(2), stat(2), write(2), fsync(3C), setflabel(3TSOL), dfstab(5), vfstab(5), attributes(7), datasets(7), filesystem(7), mount(8), shadowd(8), share(8), share_nfs(8), share_smb(8), unshare(8), zfs_allow(8), zfs_encrypt(8), zfs_share(8), zonecfg(8), zpool(8)

See the gzip (1) man page, which is not part of the Oracle Solaris man page collection.

For information about other ZFS features, see zfs_allow(8), zfs_encrypt(8), zfs_share(8), and the Managing ZFS File Systems in Oracle Solaris 11.4.

Notes

A file described as modified by the diff subcommand might have been modified in multiple ways. Any action that causes a change in the st_ctim (see stat(2)) is a basis for reporting a modification.