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:

where the maximum length of a dataset name is MAXNAMELEN (256 bytes) and the maximum amount of nesting allowed in a path is 50 levels deep.

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 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.

SUBCOMMANDS

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

zfs [-?]

Displays a help message.

zfs create [-pu] [-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.

-u

Newly created file system is not mounted.

-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/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.

-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.

-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.

zfs destroy [-fnpRrv] 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 children.

-R

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

-f

Force an unmount of any file systems using the "zfs 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.

-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 [-dnpRrv] snapshot[%snapname][,...]

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

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

-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.

-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.

-v

Print verbose information about the deleted data.

-d

Defer snapshot deletion.

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

-r

Recursively create snapshots of all descendent datasets

-o property=value

Sets the specified property; see "zfs create" for details.

zfs rollback [-rRf] 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 snapshots and bookmarks more recent than the one specified.

-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.

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.

-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.

-o property=value

Sets the specified property; see "zfs create" for details.

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 [-f] -p filesystem|volume filesystem|volume

 

zfs rename -u [-p] filesystem filesystem

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.

-p

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

-u

Do not remount file systems during rename. If a file system's mountpoint property is set to legacy or none, file system is not unmounted even if this option is not given.

-f

Force unmount any filesystems that need to be unmounted in the process. This flag has no effect if used together with the -u flag.

zfs rename -r snapshot snapshot

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

zfs rename bookmark bookmark

Renames the given bookmark. Bookmarks can only be renamed within the parent file system or volume. When renaming a bookmark, the parent file system or volume of the bookmark does not need to be specified as part of the second argument.

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

-r

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

-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.

-H

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

-p

Display numbers in parsable (exact) values.

-o property[,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.

-t type[,type]...

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

-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.

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 all | field[,field]...] [-t type[,type]...] [-s source[,source]...] 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, received, or none (-).

All columns except the RECEIVED column are displayed by default. The columns to display can be specified 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).

-r

Recursively display properties for any children.

-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.

-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

Display numbers in parsable (exact) values.

-o all | field[,field]...

A comma-separated list of columns to display. Supported values are name,property,value,received,source. Default values are name,property,value,source. The keyword all specifies all columns.

-t type[,type]...

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

-s source[,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 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 remap filesystem|volume

Remap the indirect blocks in the given filesystem or volume so that they no longer reference blocks on previously removed vdevs and we can eventually shrink the size of the indirect mapping objects for the previously removed vdevs. Note that remapping all blocks might not be possible and that references from snapshots will still exist and cannot be remapped.

zfs upgrade [-v]

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

-v

Displays ZFS filesystem versions supported by the current software. The current ZFS filesystem version and all previous 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. 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.

-r

Upgrade the specified file system and all descendent file systems.

-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.

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 and userquota@user properties.

-n

Print numeric ID instead of user/group name.

-H

Do not print headers, use tab-delimited output.

-p

Use exact (parsable) numeric output.

-o field[,field]...

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

-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.

-S field

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

-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.

-i

Translate SID to POSIX ID. This flag currently has no effect on FreeBSD.

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.

-f

 

zfs mount [-vO] [-o property[,property]...] -a | filesystem

Mounts ZFS file systems.

-v

Report mount progress.

-O

Perform an overlay mount. Overlay mounts are not supported on FreeBSD.

-o property[,property]...

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.

-a

Mount all available ZFS file systems. This command may be executed on FreeBSD system startup by /etc/rc.d/zfs. For more information, see variable zfs_enable in rc.conf(5).

filesystem

Mount the specified filesystem.

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

Unmounts currently mounted ZFS file systems.

-f

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

-a

Unmount all available ZFS file systems.

filesystem | mountpoint

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

zfs share -a | filesystem

Shares ZFS file systems that have the sharenfs property set.

-a

Share all ZFS file systems that have the sharenfs property set. This command may be executed on FreeBSD system startup by /etc/rc.d/zfs. For more information, see variable zfs_enable in rc.conf(5).

filesystem

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

zfs unshare -a | filesystem|mountpoint

Unshares ZFS file systems that have the sharenfs property set.

-a

Unshares ZFS file systems that have the sharenfs property set. This command may be executed on FreeBSD system shutdown by /etc/rc.d/zfs. For more information, see variable zfs_enable in rc.conf(5).

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(7) for details on ZFS feature flags and the bookmark feature.

zfs send [-DLPRVcenpv] [-i snapshot | -I snapshot] snapshot

Creates a stream representation of the last snapshot argument (not part of -i or -I) 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.

-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).

-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.

-R, --replicate

Generate a replication stream package, which will replicate the specified filesystem, 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.

-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 (eg. sha256).

-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(7) for details on ZFS feature flags and the large_blocks feature.

-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(7) 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.

-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.

-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, --parsable

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

-v, --verbose

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

-V

Set the process title to 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 [-LPcenv] [-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--).

-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 filesystem, 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.

-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).

-v, --verbose

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

-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(7) for details on ZFS feature flags and the large_blocks feature.

-P, --parsable

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

-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(7) for details on ZFS feature flags and the embedded_data feature.

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|recv [-vnsFu] [-o origin=snapshot] filesystem|volume|snapshot

 

zfs receive|recv [-vnsFu] [-d | -e] [-o origin=snapshot] 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.

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

Use the full sent snapshot path without the first element (without pool name) to determine the name of the new snapshot as described in the paragraph above.

-e

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

-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.

-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.

-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.

-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(7) for details on ZFS feature flags.

zfs receive|recv -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.

zfs allow [-ldug] user|group[,user|group]... perm|@setname[,perm|@setname]... filesystem|volume

 

zfs allow [-ld] -e|everyone perm|@setname[,perm|@setname]... filesystem|volume

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

[-ug] 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 -ug 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 -u or -g options. To specify a group with the same name as a user, use the -g option.

[-e|everyone]

Specifies that the permissions be delegated to "everyone".

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 an at sign (@), may be specified. See the -s form below for details.

[-ld] filesystem|volume

Specifies where the permissions are delegated. If neither of the -ld options are specified, or both are, then the permissions are allowed for the file system or volume, and all of its descendents. If only the -l option is used, then is allowed "locally" only for the specified file system. If only the -d option is used, then is allowed only for the descendent file systems.

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'
hold	subcommand	Allows adding a user hold to a snapshot
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
release	subcommand	Allows releasing a user hold which might destroy the snapshot
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 the NFS protocol
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
aclmode	property
atime	property
canmount	property
casesensitivity	property
checksum	property
compression	property
copies	property
dedup	property
devices	property
exec	property
filesystem_limit	property
logbias	property
jailed	property
mlslabel	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
sync	property
utf8only	property
version	property
volblocksize	property
volsize	property
vscan	property
xattr	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 an "at sign" (@), and can be no more than 64 characters long.

zfs unallow [-rldug] user|group[,user|group]... [perm|@setname[,perm|@setname]...] filesystem|volume

 

zfs unallow [-rld] -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 returns EBUSY.

-r

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

zfs holds [-Hp] [-r|-d depth] filesystem|volume|snapshot...

Lists all existing user references for the given dataset or datasets.

-H

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

-p

Display numbers in parsable (exact) values.

-r

Lists the holds that are set on the descendent snapshots of the named datasets or snapshots, in addition to listing the holds on the named snapshots, if any.

-d depth

Recursively display any holds on the named snapshots, or descendent snapshots of the named datasets or snapshots, limiting the recursion to depth.

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.

-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:

-	path was removed
+	path was added
M	path was modified
R	path was renamed

-F

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

B	block device
C	character device
F	regular file
/	directory
@	symbolic link
=	socket
>	door (not supported on FreeBSD)
|	named pipe (not supported on FreeBSD)
P	event port (not supported on FreeBSD)

-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.

zfs program [-jn] [-t timeout] [-m memory_limit] pool script [arg1 ...]

Executes script as a ZFS channel program on pool. The ZFS channel program interface allows ZFS administrative operations to be run programmatically via a Lua script. The entire script is executed atomically, with no other administrative operations taking effect concurrently. A library of ZFS calls is made available to channel program scripts. Channel programs may only be run with root privileges.

For full documentation of the ZFS channel program interface, see the manual page for zfs-program(8).

-j

Display channel program output in JSON format. When this flag is specified and standard output is empty - channel program encountered an error. The details of such an error will be printed to standard error in plain text.

-n

Executes a read-only channel program, which runs faster. The program cannot change on-disk state by calling functions from the zfs.sync submodule. The program can be used to gather information such as properties and determining if changes would succeed (zfs.check.*). Without this flag, all pending changes must be synced to disk before a channel program can complete.

-t timeout

Execution time limit, in milliseconds. If a channel program executes for longer than the provided timeout, it will be stopped and an error will be returned. The default timeout is 1000 ms, and can be set to a maximum of 10000 ms.

-m memory-limit

Memory limit, in bytes. If a channel program attempts to allocate more memory than the given limit, it will be stopped and an error returned. The default memory limit is 10 MB, and can be set to a maximum of 100 MB.

All remaining argument strings are passed directly to the channel program as arguments. See zfs-program(8) for more information.

zfs jail jailid filesystem

Attaches the specified filesystem to the jail identified by JID jailid. From now on this file system tree can be managed from within a jail if the jailed property has been set. To use this functionality, the jail needs the allow.mount and allow.mount.zfs parameters set to 1 and the enforce_statfs parameter set to a value lower than 2.

See jail(8) for more information on managing jails and configuring the parameters above.

zfs unjail jailid filesystem

Detaches the specified filesystem from the jail identified by JID jailid.

EXIT STATUS

The following exit values are returned:

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 /home is set for the parent file system, and is automatically inherited by the child file system.

# zfs create pool/home
# zfs set mountpoint=/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  /home
   pool/home/anne             18K   457G    18K  /home/anne
   pool/home/bob             276K   457G   276K  /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            /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  filesystem_limit      none                   default
pool/home/bob  setuid                on                     default
pool/home/bob  readonly              off                    default
pool/home/bob  jailed                off                    default
pool/home/bob  snapdir               hidden                 default
pool/home/bob  snapshot_limit        none                   default
pool/home/bob  aclmode               discard                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               5                      -
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                      -
pool/home/bob  logbias               latency                default
pool/home/bob  dedup                 off                    default
pool/home/bob  mlslabel                                     -
pool/home/bob  sync                  standard               default
pool/home/bob  refcompressratio      1.00x                  -

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 -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 and continue with the following commands:

# zfs snapshot pool/project/production@today
# zfs clone pool/project/production@today pool/project/beta

Now make changes to /pool/project/beta and continue with the following commands:

# 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@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 Setting "sharenfs" Property Options on a ZFS File System

The following command shows how to set sharenfs property options to enable root access for a specific network on the tank/home file system. The contents of the sharenfs property are valid exports(5) options.

# zfs set sharenfs="maproot=root,network 192.168.0.0/24" tank/home

Another way to write this command with the same result is:

# set zfs sharenfs="-maproot=root -network 192.168.0.0/24" tank/home

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

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
# su - cindys
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 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

SEE ALSO

chmod(2), fsync(2), exports(5), fstab(5), rc.conf(5), jail(8), mount(8), umount(8), zfs-program(8), zpool(8)

HISTORY

The zfs utility first appeared in FreeBSD 7.0.

AUTHORS

This manual page is a mdoc(7) reimplementation of the OpenSolaris manual page zfs(1M), modified and customized for FreeBSD and licensed under the Common Development and Distribution License (CDDL).

The mdoc(7) implementation of this manual page was initially written by Martin Matuska ⟨mm@FreeBSD.org⟩.