NAME

zfs — configures ZFS file systems

SYNOPSIS

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 non-standard behavior when checking file system free 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.

bookmark

Much like a snapshot, but without the hold on on-disk data. It can be used as the source of a send (but not for a receive). It is specified as filesystem#name or volume#name.

    PROPERTY                MOUNT OPTION
    atime                   atime/noatime
    canmount                auto/noauto
    devices                 dev/nodev
    exec                    exec/noexec
    readonly                ro/rw
    relatime                relatime/norelatime
    setuid                  suid/nosuid
    xattr                   xattr/noxattr

SUBCOMMANDS

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

zfs -?

Displays a help message.

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.

-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.

-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.

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/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 Kbytes to ensure that the volume has an integral number of blocks regardless of blocksize.

-b blocksize

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

-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.

-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.

zfs destroy [-Rfnprv] filesystem|volume

Destroys the given dataset. 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).

-R

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

-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.

-n

Do a dry-run ("No-op") deletion. No data will be deleted. This is useful in conjunction with the -v or -p flags to determine what data would be deleted.

-p

Print machine-parsable verbose information about the deleted data.

-r

Recursively destroy all children.

-v

Print verbose information about the deleted data.

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

zfs destroy [-Rdnprv] filesystem|volume@snap[%snap[,snap[%snap]]]...

The given snapshots are 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 a 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.

An inclusive range of snapshots may be specified by separating the first and last snapshots with a percent sign. The first and/or last snapshots may be left blank, in which case the filesystem's oldest or newest snapshot will be implied.

Multiple snapshots (or ranges of snapshots) of the same filesystem or volume may be specified in a comma-separated list of snapshots. Only the snapshot's short name (the part after the @) should be specified when using a range or comma-separated list to identify multiple snapshots.

-R

Recursively destroy all clones of these snapshots, including the clones, snapshots, and children. If this flag is specified, the -d flag will have no effect.

-d

Defer snapshot deletion.

-n

Do a dry-run ("No-op") deletion. No data will be deleted. This is useful in conjunction with the -p or -v flags to determine what data would be deleted.

-p

Print machine-parsable verbose information about the deleted data.

-r

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

-v

Print verbose information about the deleted data.

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

zfs destroy filesystem|volume#bookmark

The given bookmark is destroyed.

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

Creates snapshots with the given names. All previous modifications by successful system calls to the file system are part of the snapshots. Snapshots are taken atomically, so that all snapshots correspond to the same moment in time. See the Snapshots section for details.

-o property=value

Sets the specified property; see zfs create for details.

-r

Recursively create snapshots of all descendent datasets

zfs rollback [-Rfr] snapshot

Roll 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 and bookmarks must be destroyed by specifying the -r option.

The -rR options do not recursively destroy the child snapshots of a recursive snapshot. Only direct snapshots of the specified filesystem are destroyed by either of these options. To completely roll back a recursive snapshot, you must rollback the individual child snapshots.

-R

Destroy any more recent snapshots and bookmarks, 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.

-r

Destroy any snapshots and bookmarks more recent than the one specified.

zfs clone [-p] [-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.

-o property=value

Sets the specified property; see zfs create for details.

-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 filesystem or volume already exists, the operation completes successfully.

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 rename [-f] filesystem|volume|snapshot filesystem|volume|snapshot

 

zfs rename [-fp] 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.

-f

Force unmount any filesystems that need to be unmounted in the process.

-p

Creates all the nonexistent 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 rename the snapshots of all descendent datasets. Snapshots are the only dataset that can be renamed recursively.

zfs list [-r|-d depth] [-Hp] [-o property[,property]...] [-s property]... [-S property]... [-t type[,type]...] [filesystem|volume|snapshot]...

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). 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.

-S property

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

-d depth

Recursively display any children of the dataset, limiting the recursion to 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.

-p

Display numbers in parsable (exact) values.

-r

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

-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.

-t type

A comma-separated list of types to display, where type is one of filesystem, snapshot, volume, bookmark, or all. For example, specifying -t snapshot displays only snapshots.

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

Sets the property or list of properties to the given value(s) 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.

zfs get [-r|-d depth] [-Hp] [-o field[,field]...] [-s source[,source]...] [-t type[,type]...] all | property[,property]... filesystem|volume|snapshot|bookmark...

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 are displayed by default, though this can be controlled by 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, snapshot, or bookmark).

-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.

-d depth

Recursively display 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

A comma-separated list of columns to display. name,property,value,source is the default value.

-p

Display numbers in parsable (exact) values.

-r

Recursively display properties for any children.

-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, and none. The default value is all sources.

-t type

A comma-separated list of types to display, where type is one of filesystem, snapshot, volume, bookmark, or all.

zfs inherit [-rS] property filesystem|volume|snapshot...

Clears the specified property, causing it to be inherited from an ancestor, restored to default if no ancestor has the property set, or with the -S option reverted to the received value if one exists. See the Properties section for a listing of default values, and details on which properties can be inherited.

-r

Recursively inherit the given property for all children.

-S

Revert the property to the received value if one exists; otherwise operate as if the -S option was not specified.

zfs upgrade

Displays a list of file systems that are not the most recent version.

zfs upgrade -v

Displays a list of currently supported file system versions.

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

Upgrades file systems to a new on-disk version. Once this is done, the file systems will no longer be accessible on systems running older versions of the software. zfs send streams generated from new snapshots of these file systems cannot be accessed on systems running older versions of the software.

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.

-V version

Upgrade 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.

-a

Upgrade all file systems on all imported pools.

filesystem

Upgrade the specified file system.

-r

Upgrade the specified file system and all descendent file systems.

zfs userspace [-Hinp] [-o field[,field]...] [-s field]... [-S field]... [-t type[,type]...] filesystem|snapshot

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

-H

Do not print headers, use tab-delimited output.

-S field

Sort by this field in reverse order. See -s.

-i

Translate 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 will be 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.

-n

Print numeric ID instead of user/group name.

-o field[,field]...

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

-p

Use exact (parsable) numeric output.

-s field

Sort 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.

-t type[,type]...

Print 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.

zfs groupspace [-Hinp] [-o field[,field]...] [-s field]... [-S field]... [-t type[,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 mount

Displays all ZFS file systems currently mounted.

zfs mount [-Ov] [-o options] -a | filesystem

Mounts ZFS file systems.

-O

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

-a

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

filesystem

Mount the specified filesystem.

-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.

-v

Report mount progress.

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

Unmounts currently mounted ZFS file systems.

-a

Unmount all available ZFS file systems. Invoked automatically as part of the shutdown process.

filesystem|mountpoint

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

-f

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

zfs share -a | filesystem

Shares available ZFS file systems.

-a

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

filesystem

Share the specified filesystem according to the sharenfs and sharesmb properties. File systems are shared when the sharenfs or sharesmb property is set.

zfs unshare -a | filesystem|mountpoint

Unshares currently shared ZFS file systems.

-a

Unshare all available ZFS file systems. Invoked automatically as part of the shutdown process.

filesystem|mountpoint

Unshare the specified filesystem. The command can also be given a path to a ZFS file system shared on the system.

zfs bookmark snapshot bookmark

Creates a bookmark of the given snapshot. Bookmarks mark the point in time when the snapshot was created, and can be used as the incremental source for a zfs send command.

This feature must be enabled to be used. See zpool-features(5) for details on ZFS feature flags and the bookmarks feature.

zfs send [-DLPRcenpv] [[-I|-i] snapshot] 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.

-D, --dedup

Generate a deduplicated stream. Blocks which would have been sent multiple times in the send stream will only be sent once. The receiving system must also support this feature to receive a deduplicated stream. This flag can be used regardless of the dataset's dedup property, but performance will be much better if the filesystem uses a dedup-capable checksum (for example, sha256).

-I snapshot

Generate 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 may be specified as with the -i option.

-L, --large-block

Generate a stream which may contain blocks larger than 128KB. This flag has no effect if the large_blocks pool feature is disabled, or if the recordsize property of this filesystem has never been set above 128KB. The receiving system must have the large_blocks pool feature enabled as well. See zpool-features(5) for details on ZFS feature flags and the large_blocks feature.

-P, --parsable

Print machine-parsable verbose information about the stream package generated.

-R, --replicate

Generate a replication stream package, which will replicate 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.

-e, --embed

Generate a more compact stream by using WRITE_EMBEDDED records for blocks which are stored more compactly on disk by the embedded_data pool feature. This flag has no effect if the embedded_data feature is disabled. The receiving system must have the embedded_data feature enabled. If the lz4_compress feature is active on the sending system, then the receiving system must have that feature enabled as well. See zpool-features(5) for details on ZFS feature flags and the embedded_data feature.

-c, --compressed

Generate a more compact stream by using compressed WRITE records for blocks which are compressed on disk and in memory (see the compression property for details). If the lz4_compress feature is active on the sending system, then the receiving system must have that feature enabled as well. If the large_blocks feature is enabled on the sending system but the -L option is not supplied in conjunction with -c, then the data will be decompressed before sending so it can be split into smaller block sizes.

-i snapshot

Generate an incremental stream from the first snapshot (the incremental source) to the second snapshot (the incremental target). The incremental source can be specified as the last component of the snapshot name (the @ character and following) and it is assumed to be from the same file system as the incremental target.

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).

-n, --dryrun

Do a dry-run ("No-op") send. Do not generate any actual send data. This is useful in conjunction with the -v or -P flags to determine what data will be sent. In this case, the verbose output will be written to standard output (contrast with a non-dry-run, where the stream is written to standard output and the verbose output goes to standard error).

-p, --props

Include the dataset's properties in the stream. This flag is implicit when -R is specified. The receiving system must also support this feature.

-v, --verbose

Print verbose information about the stream package generated. This information includes a per-second report of how much data has been sent.

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

zfs send [-Lce] [-i snapshot|bookmark] filesystem|volume|snapshot

Generate a send stream, which may be of a filesystem, and may be incremental from a bookmark. If the destination is a filesystem or volume, the pool must be read-only, or the filesystem must not be mounted. When the stream generated from a filesystem or volume is received, the default snapshot name will be "--head--".

-L, --large-block

Generate a stream which may contain blocks larger than 128KB. This flag has no effect if the large_blocks pool feature is disabled, or if the recordsize property of this filesystem has never been set above 128KB. The receiving system must have the large_blocks pool feature enabled as well. See zpool-features(5) for details on ZFS feature flags and the large_blocks feature.

-c, --compressed

Generate a more compact stream by using compressed WRITE records for blocks which are compressed on disk and in memory (see the compression property for details). If the lz4_compress feature is active on the sending system, then the receiving system must have that feature enabled as well. If the large_blocks feature is enabled on the sending system but the -L option is not supplied in conjunction with -c, then the data will be decompressed before sending so it can be split into smaller block sizes.

-e, --embed

Generate a more compact stream by using WRITE_EMBEDDED records for blocks which are stored more compactly on disk by the embedded_data pool feature. This flag has no effect if the embedded_data feature is disabled. The receiving system must have the embedded_data feature enabled. If the lz4_compress feature is active on the sending system, then the receiving system must have that feature enabled as well. See zpool-features(5) for details on ZFS feature flags and the embedded_data feature.

-i snapshot|bookmark

Generate an incremental send stream. The incremental source must be an earlier snapshot in the destination's history. It will commonly be an earlier snapshot in the destination's file system, in which case it can be specified as the last component of the name (the # or @ character and following).

If the incremental target is a clone, the incremental source can be the origin snapshot, or an earlier snapshot in the origin's filesystem, or the origin's origin, etc.

zfs send [-Penv] -t receive_resume_token

Creates a send stream which resumes an interrupted receive. The receive_resume_token is the value of this property on the filesystem or volume that was being received into. See the documentation for zfs receive -s for more details.

zfs receive [-Fnsuv] [-o origin=snapshot] [-o property=value] [-x property] filesystem|volume|snapshot

 

zfs receive [-Fnsuv] [-d|-e] [-o origin=snapshot] [-o property=value] [-x property] filesystem

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 zvols, the destination device link is destroyed and recreated, which means the zvol 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 will be set ( -o ) or inherited ( -x ) on the topmost in the replicated subtree. In descendant datasets, if the property is set by the send stream, it will be overridden by forcing the property to be inherited from the top‐most file system. Received properties are retained in spite of being overridden and may be restored with zfs inherit -S. Specifying -o origin=snapshot is a special case because, even if origin is a read-only property and cannot be set, it's allowed to receive the send stream as a clone of the given snapshot.

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 use of the -d or -e options.

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 neither of the -d or -e options are specified, the provided target snapshot name is used exactly as provided.

The -d and -e options cause the file system name of the target snapshot to be determined by appending a portion of the sent snapshot's name to the specified target filesystem. If the -d option is specified, all but the first element of the sent snapshot's file system path (usually the pool name) is used and any required intermediate file systems within the specified one are created. If the -e option is specified, then only the last element of the sent snapshot's file system name (i.e. the name of the source file system itself) is used as the target file system name.

-F

Force 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 [-i|-I]), destroy snapshots and file systems that do not exist on the sending side.

-d

Discard the first element of the sent snapshot's file system name, using the remaining elements to determine the name of the target file system for the new snapshot as described in the paragraph above.

-e

Discard all but the last element of the sent snapshot's file system name, using that element to determine the name of the target file system for the new snapshot as described in the paragraph above.

-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.

-o origin=snapshot

Forces the stream to be received as a clone of the given snapshot. If the stream is a full send stream, this will create the filesystem described by the stream as a clone of the specified snapshot. Which snapshot was specified will not affect the success or failure of the receive, as long as the snapshot does exist. If the stream is an incremental send stream, all the normal verification will be performed.

-o property=value

Sets the specified property as if the command zfs set property=value was invoked immediately before the receive. When receiving a stream from zfs send -R, causes the property to be inherited by all descendant datasets, as through zfs inherit property was run on any descendant datasets that have this property set on the sending system.

Any editable property can 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. Additionally both settable properties version and volsize cannot be set at receive time.

The -o option may be specified multiple times, for different properties. An error results if the same property is specified in multiple -o or -x options.

-s

If the receive is interrupted, save the partially received state, rather than deleting it. Interruption may be due to premature termination of the stream (e.g. due to network failure or failure of the remote system if the stream is being read over a network connection), a checksum error in the stream, termination of the zfs receive process, or unclean shutdown of the system.

The receive can be resumed with a stream generated by zfs send -t token, where the token is the value of the receive_resume_token property of the filesystem or volume which is received into.

To use this flag, the storage pool must have the extensible_dataset feature enabled. See zpool-features(5) for details on ZFS feature flags.

-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 will be set or inherited, depending on whether the property is inheritable or not.

In the case of an incremental update, -x leaves any existing local setting or explicit inheritance unchanged.

All -o restrictions on set-once and special properties apply equally to -x.

zfs receive -A filesystem|volume

Abort an interrupted zfs receive -s, deleting its saved partially received state.

zfs allow filesystem|volume

Displays permissions that have been delegated on the specified filesystem or volume. See the other forms of zfs allow for more information.

Delegations are supported under Linux with the exception of mount, unmount, mountpoint, canmount, rename, and share. These permissions cannot be delegated because the Linux mount(8) command restricts modifications of the global namespace to the root user.

zfs allow [-dglu] user|group[,user|group]... perm|@setname[,perm|@setname]... filesystem|volume
zfs allow [-dl] -e|everyone perm|@setname[,perm|@setname]... filesystem|volume

Delegates ZFS administration permission for the file systems to non-privileged users.

-d

Allow only for the descendent file systems.

-e|everyone

Specifies that the permissions be delegated to everyone.

-g group[,group]...

Explicitly specify that permissions are delegated to the group.

-l

Allow "locally" only for the specified file system.

-u user[,user]...

Explicitly specify that permissions are delegated to the user.

user|group[,user|group]...

Specifies to whom the permissions are delegated. Multiple entities can be specified as a comma-separated list. If neither of the -gu options are specified, then the argument is interpreted preferentially as the keyword everyone, then as a user name, and lastly as a group name. To specify a user or group named "everyone", use the -g or -u options. To specify a group with the same name as a user, use the -g options.

perm|@setname[,perm|@setname]...

The permissions to delegate. Multiple permissions may be specified as a comma-separated list. Permission names are the same as ZFS subcommand and property names. See the property list below. Property set names, which begin with @, may be specified. See the -s form below for details.

If neither of the -dl options are specified, or both are, then the permissions are allowed for the file system or volume, and all of its descendents.

Permissions are generally the ability to use a ZFS subcommand or change a ZFS property. The following permissions are available:

NAME             TYPE           NOTES
allow            subcommand     Must also have the permission that is
                                being allowed
clone            subcommand     Must also have the 'create' ability and
                                'mount' ability in the origin file system
create           subcommand     Must also have the 'mount' ability
destroy          subcommand     Must also have the 'mount' ability
diff             subcommand     Allows lookup of paths within a dataset
                                given an object number, and the ability
                                to create snapshots necessary to
                                'zfs diff'.
mount            subcommand     Allows mount/umount of ZFS datasets
promote          subcommand     Must also have the 'mount' and 'promote'
                                ability in the origin file system
receive          subcommand     Must also have the 'mount' and 'create'
                                ability
rename           subcommand     Must also have the 'mount' and 'create'
                                ability in the new parent
rollback         subcommand     Must also have the 'mount' ability
send             subcommand
share            subcommand     Allows sharing file systems over NFS
                                or SMB protocols
snapshot         subcommand     Must also have the 'mount' ability

groupquota       other          Allows accessing any groupquota@...
                                property
groupused        other          Allows reading any groupused@... property
userprop         other          Allows changing any user property
userquota        other          Allows accessing any userquota@...
                                property
userused         other          Allows reading any userused@... property

aclinherit       property
acltype          property
atime            property
canmount         property
casesensitivity  property
checksum         property
compression      property
copies           property
devices          property
exec             property
filesystem_limit property
mountpoint       property
nbmand           property
normalization    property
primarycache     property
quota            property
readonly         property
recordsize       property
refquota         property
refreservation   property
reservation      property
secondarycache   property
setuid           property
sharenfs         property
sharesmb         property
snapdir          property
snapshot_limit   property
utf8only         property
version          property
volblocksize     property
volsize          property
vscan            property
xattr            property
zoned            property

zfs allow -c perm|@setname[,perm|@setname]... filesystem|volume

Sets "create time" permissions. These permissions are granted (locally) to the creator of any newly-created descendent file system.

zfs allow -s @setname perm|@setname[,perm|@setname]... filesystem|volume

Defines or adds permissions to a permission set. The set can be used by other zfs allow commands for the specified file system and its descendents. Sets are evaluated dynamically, so changes to a set are immediately reflected. Permission sets follow the same naming restrictions as ZFS file systems, but the name must begin with @, and can be no more than 64 characters long.

zfs unallow [-dglru] user|group[,user|group]... [perm|@setname[,perm|@setname]...] filesystem|volume
zfs unallow [-dlr] -e|everyone [perm|@setname[,perm|@setname]...] filesystem|volume
zfs unallow [-r] -c [perm|@setname[,perm|@setname]...] filesystem|volume

Removes permissions that were granted with the zfs allow command. No permissions are explicitly denied, so other permissions granted are still in effect. For example, if the permission is granted by an ancestor. If no permissions are specified, then all permissions for the specified user, group, or everyone are removed. Specifying everyone (or using the -e option) only removes the permissions that were granted to everyone, not all permissions for every user and group. See the zfs allow command for a description of the -ldugec options.

-r

Recursively remove the permissions from this file system and all descendents.

zfs unallow [-r] -s @setname [perm|@setname[,perm|@setname]...] filesystem|volume

Removes permissions from a permission set. If no permissions are specified, then all permissions are removed, thus removing the set entirely.

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 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 diff [-FHt] snapshot snapshot|filesystem

Display the difference between a snapshot of a given filesystem and another snapshot of that filesystem from a later time or the current contents of the filesystem. The first column is a character indicating the type of change, the other columns indicate pathname, new pathname (in case of rename), change in link count, and optionally file type and/or change time. The types of change are:

-       The path has been removed
+       The path has been created
M       The path has been modified
R       The path has been renamed

-F

Display an indication of the type of file, in a manner similar to the - option of ls(1).

B       Block device
C       Character device
/       Directory
>       Door
|       Named pipe
@       Symbolic link
P       Event port
=       Socket
F       Regular file

-H

Give more parsable tab-separated output, without header lines and without arrows.

-t

Display the path's inode change time as the first column of output.

EXIT STATUS

The zfs utility exits 0 on success, 1 if an error occurs, and 2 if invalid command line options were specified.

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. 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 50 Gbytes for pool/home/bob.

# zfs set quota=50G 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  type                  filesystem             -
pool/home/bob  creation              Tue Jul 21 15:53 2009  -
pool/home/bob  used                  21K                    -
pool/home/bob  available             20.0G                  -
pool/home/bob  referenced            21K                    -
pool/home/bob  compressratio         1.00x                  -
pool/home/bob  mounted               yes                    -
pool/home/bob  quota                 20G                    local
pool/home/bob  reservation           none                   default
pool/home/bob  recordsize            128K                   default
pool/home/bob  mountpoint            /pool/home/bob         default
pool/home/bob  sharenfs              off                    default
pool/home/bob  checksum              on                     default
pool/home/bob  compression           on                     local
pool/home/bob  atime                 on                     default
pool/home/bob  devices               on                     default
pool/home/bob  exec                  on                     default
pool/home/bob  setuid                on                     default
pool/home/bob  readonly              off                    default
pool/home/bob  zoned                 off                    default
pool/home/bob  snapdir               hidden                 default
pool/home/bob  acltype               off                    default
pool/home/bob  aclinherit            restricted             default
pool/home/bob  canmount              on                     default
pool/home/bob  xattr                 on                     default
pool/home/bob  copies                1                      default
pool/home/bob  version               4                      -
pool/home/bob  utf8only              off                    -
pool/home/bob  normalization         none                   -
pool/home/bob  casesensitivity       sensitive              -
pool/home/bob  vscan                 off                    default
pool/home/bob  nbmand                off                    default
pool/home/bob  sharesmb              off                    default
pool/home/bob  refquota              none                   default
pool/home/bob  refreservation        none                   default
pool/home/bob  primarycache          all                    default
pool/home/bob  secondarycache        all                    default
pool/home/bob  usedbysnapshots       0                      -
pool/home/bob  usedbydataset         21K                    -
pool/home/bob  usedbychildren        0                      -
pool/home/bob  usedbyrefreservation  0                      -

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  quota                 20G
pool/home/bob  compression           on

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@a and 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

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@yesterday @5daysago
# zfs rename -r pool/users@yesterday @4daysago
# zfs rename -r pool/users@yesterday @3daysago
# zfs rename -r pool/users@yesterday @2daysago
# zfs rename -r pool/users@today @yesterday
# zfs snapshot -r pool/users@today

Example 16 Setting sharenfs Property Options on a ZFS File System

The following commands show how to set sharenfs property options to enable rw access for a set of IP addresses and to enable root access for system neo on the tank/home file system.

# zfs set sharenfs='rw=@123.123.0.0/16,root=neo' tank/home

If you are using DNS for host name resolution, specify the fully qualified hostname.

Example 17 Delegating ZFS Administration Permissions on a ZFS Dataset

The following example shows how to set permissions so that user cindys can create, destroy, mount, and take snapshots on tank/cindys. The permissions on tank/cindys are also displayed.

# zfs allow cindys create,destroy,mount,snapshot tank/cindys
# zfs allow tank/cindys
---- Permissions on tank/cindys --------------------------------------
Local+Descendent permissions:
        user cindys create,destroy,mount,snapshot

Because the tank/cindys mount point permission is set to 755 by default, user cindys will be unable to mount file systems under tank/cindys. Add an ACE similar to the following syntax to provide mount point access:

# chmod A+user:cindys:add_subdirectory:allow /tank/cindys

Example 18 Delegating Create Time Permissions on a ZFS Dataset

The following example shows how to grant anyone in the group staff to create file systems in tank/users. This syntax also allows staff members to destroy their own file systems, but not destroy anyone else's file system. The permissions on tank/users are also displayed.

# zfs allow staff create,mount tank/users
# zfs allow -c destroy tank/users
# zfs allow tank/users
---- Permissions on tank/users ---------------------------------------
Permission sets:
        destroy
Local+Descendent permissions:
        group staff create,mount

Example 19 Defining and Granting a Permission Set on a ZFS Dataset

The following example shows how to define and grant a permission set on the tank/users file system. The permissions on tank/users are also displayed.

# zfs allow -s @pset create,destroy,snapshot,mount tank/users
# zfs allow staff @pset tank/users
# zfs allow tank/users
---- Permissions on tank/users ---------------------------------------
Permission sets:
        @pset create,destroy,mount,snapshot
Local+Descendent permissions:
        group staff @pset

Example 20 Delegating Property Permissions on a ZFS Dataset

The following example shows to grant the ability to set quotas and reservations on the users/home file system. The permissions on users/home are also displayed.

# zfs allow cindys quota,reservation users/home
# zfs allow users/home
---- Permissions on users/home ---------------------------------------
Local+Descendent permissions:
        user cindys quota,reservation
cindys% zfs set quota=10G users/home/marks
cindys% zfs get quota users/home/marks
NAME              PROPERTY  VALUE  SOURCE
users/home/marks  quota     10G    local

Example 21 Removing ZFS Delegated Permissions on a ZFS Dataset

The following example shows how to remove the snapshot permission from the staff group on the tank/users file system. The permissions on tank/users are also displayed.

# zfs unallow staff snapshot tank/users
# zfs allow tank/users
---- Permissions on tank/users ---------------------------------------
Permission sets:
        @pset create,destroy,mount,snapshot
Local+Descendent permissions:
        group staff @pset

Example 22 Showing the differences between a snapshot and a ZFS Dataset

The following example shows how to see what has changed between a prior snapshot of a ZFS dataset and its current state. The -F option is used to indicate type information for the files affected.

# zfs diff -F tank/test@before tank/test
M       /       /tank/test/
M       F       /tank/test/linked      (+1)
R       F       /tank/test/oldname -> /tank/test/newname
-       F       /tank/test/deleted
+       F       /tank/test/created
M       F       /tank/test/modified

Example 23 Creating a bookmark

The following example create a bookmark to a snapshot. This bookmark can then be used instead of snapshot in send streams.

# zfs bookmark rpool@snapshot rpool#bookmark

Example 24 Setting sharesmb Property Options on a ZFS File System

The following example show how to share SMB filesystem through ZFS. Note that that a user and his/her password must be given.

# smbmount //127.0.0.1/share_tmp /mnt/tmp \
  -o user=workgroup/turbo,password=obrut,uid=1000

Minimal /etc/samba/smb.conf configuration required:

Samba will need to listen to 'localhost' (127.0.0.1) for the ZFS utilities to communicate with Samba. This is the default behavior for most Linux distributions.

Samba must be able to authenticate a user. This can be done in a number of ways, depending on if using the system password file, LDAP or the Samba specific smbpasswd file. How to do this is outside the scope of this manual. Please refer to the smb.conf(5) man page for more information.

See the USERSHARE section of the smb.conf(5) man page for all configuration options in case you need to modify any options to the share afterwards. Do note that any changes done with the net(8) command will be undone if the share is ever unshared (such as at a reboot etc).

INTERFACE STABILITY

Committed.

SEE ALSO

gzip(1), ssh(1), mount(8), zpool(8), selinux(8), chmod(2), stat(2), write(2), fsync(2), attr(1), acl(5), exports(5), exportfs(8), net(8), attributes(5)