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Managing ZFS File Systems in Oracle® Solaris 11.4

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Updated: February 2021

ZFS Glossary

boot environment

A bootable Oracle Solaris environment consisting of a ZFS root file system and, optionally, other file systems mounted underneath it. Exactly one boot environment can be active at a time.


A 256-bit hash of the data in a file system block. The checksum capability can range from the simple and fast fletcher4 (the default) to cryptographically strong hashes such as SHA256.


A file system whose initial contents are identical to the contents of a snapshot.

For information about clones, see Overview of ZFS Clones.


A generic name for the following ZFS components: clones, file systems, snapshots, and volumes. Each dataset is identified by a unique name in the ZFS namespace.

For more information about datasets, see Managing Oracle Solaris ZFS File Systems.


The process of eliminating duplicate blocks of data in a ZFS file system. After removing duplicate blocks, the unique blocks are stored in the deduplication table.

file system

A ZFS dataset of type filesystem that is mounted within the standard system namespace and behaves like other file systems.

For more information about file systems, see Managing Oracle Solaris ZFS File Systems.


A virtual device that stores identical copies of data on two or more disks. If any disk in a mirror fails, any other disk in that mirror can provide the same data.


A logical group of devices describing the layout and physical characteristics of the available storage. Disk space for datasets is allocated from a pool.

For more information about storage pools, see Managing Oracle Solaris ZFS Storage Pools.


A virtual device that stores data and parity on multiple disks. For more information about RAID-Z, see RAID-Z Storage Pool Configuration.


The process of copying data from one device to another device. For example, if a mirror device is replaced or taken offline, the data from an up-to-date mirror device is copied to the newly restored mirror device. In traditional volume management products, this process is referred to as mirror resynchronization.

For more information about ZFS resilvering, see Viewing Resilvering Status.

root pool

A ZFS pool that contains the boot file system.


A read-only copy of a file system or volume at a given point in time.

For more information about snapshots, see Overview of ZFS Snapshots.

virtual device

A logical device in a pool, which can be a physical device, a file, or a collection of devices.

For more information about virtual devices, see Querying ZFS Storage Pool Status.


A dataset that represents a block device. For example, you can create a ZFS volume as a swap device.

For more information about ZFS volumes, see ZFS Volumes.