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Managing ZFS File Systems in Oracle® Solaris 11.4

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Updated: July 2019
 
 

Managing ZFS Storage Pool Properties

To manage ZFS pool properties, you use the following commands:

  • zpool get all pool – Lists all the properties of the pool with their corresponding values.

  • zpool get property pool – Lists the specified property of the pool with its corresponding value.

  • zpool set property=value pool – Assigns a value to the pool's specified property.

If you attempt to set a pool property on a pool that is full, a message similar to the following is displayed:

$ zpool set autoreplace=on system1
cannot set property for 'system1': out of space

For information on preventing pool space capacity problems, see Recommended Oracle Solaris ZFS Practices.

Table 2  ZFS Pool Property Descriptions
Property Name
Type
Default Value
Description
allocated
String
N/A
Read-only value that identifies the amount of storage space within the pool that has been physically allocated.
altroot
String
off
Identifies an alternate root directory. If set, this directory is prepended to any mount points within the pool. This property can be used in the following situations: when you are examining an unknown pool, if the mount points cannot be trusted, or in an alternate boot environment where the typical paths are not valid.
autoreplace
Boolean
off
Controls automatic device replacement. If set to off, you must initiate device replacement using the zpool replace command. If set to on, any new device found in the same physical location as a device that previously belonged to the pool is automatically formatted and replaced. The property abbreviation is replace.
bootfs
Boolean
N/A
Identifies the default bootable file system for the root pool. This property is typically set by the installation programs.
cachefile
String
N/A
Controls where pool configuration information is cached. All pools in the cache are automatically imported when the system boots. However, installation and clustering environments might require this information to be cached in a different location so that pools are not automatically imported. You can set this property to cache pool configuration information in a different location. This information can be imported later by using the zpool import –c command.
For most ZFS configurations, this property is not used.
capacity
Number
N/A
Read-only value that identifies the percentage of pool space used.
The property abbreviation is cap.
clustered
String
off
Provides support for global mounting of a ZFS file system in an Oracle Solaris Cluster environment.
dedupditto
String
N/A
Sets a threshold for the reference count for a deduped block. If the count goes above the threshold, another ditto copy of the block is stored automatically.
dedupratio
String
N/A
Read-only deduplication ratio achieved for a pool, expressed as a multiplier.
delegation
Boolean
on
Controls whether a nonprivileged user can be granted access permissions that are defined for a file system. For more information, see Oracle Solaris ZFS Delegated Administration.
failmode
String
wait
Controls the system behavior if a catastrophic pool failure occurs. This condition is typically a result of a loss of connectivity to the underlying storage device or devices or a failure of all devices within the pool. The behavior of such an event is determined by one of the following values:
  • wait – Blocks all I/O requests to the pool until device connectivity is restored and the errors are cleared by using the zpool clear command. In this state, I/O operations to the pool are blocked but read operations might succeed. A pool remains in the wait state until the device issue is resolved.

  • continue – Returns an EIO error to any new write I/O requests but allows reads to any of the remaining healthy devices. Any write requests that have yet to be committed to disk are blocked. After the device is reconnected or replaced, the errors must be cleared with the zpool clear command.

  • panic – Prints a message to the console and generates a system crash dump.

free
String
N/A
Read-only value that identifies the number of blocks within the pool that are not allocated.
guid
String
N/A
Read-only property that identifies the unique identifier for the pool.

Caution  -  If you are using multiple pools, make sure that they all have unique GUIDs. Shared GUIDs among pools might result in unexpected behavior.

health
String
N/A
Read-only property that identifies the current health of the pool, as either ONLINE, DEGRADED, SUSPENDED, REMOVED, or UNAVAIL.
listshares
String
off
Controls whether share information in this pool is displayed with the zfs list command. The default value is off.
listsnapshots
String
off
Controls whether snapshot information that is associated with this pool is displayed with the zfs list command. If this property is disabled, you can display snapshot information with the zfs list –t snapshot command.
readonly
Boolean
off
Identifies whether a pool can be modified. This property is enabled only when a pool is has been imported in read-only mode. If enabled, any synchronous data that exists only in the intent log will not be accessible until the pool is re-imported in read-write mode.
size
Number
N/A
Read-only property that identifies the total size of the storage pool.
version
Number
N/A
Identifies the current on-disk version of the pool. The preferred method of updating pools is with the zpool upgrade command, although you can use this property when you need a specific version for backwards compatibility. You can set this property to any number between 1 and the current version reported by the zpool upgrade –v command.