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ZFS(8) FreeBSD System Manager's Manual ZFS(8) NAME zfs - configure ZFS datasets SYNOPSIS zfs -?V zfs version zfs subcommand [arguments] 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: pool[/component]/component for example: rpool/var/log The maximum length of a dataset name is ZFS_MAX_DATASET_NAME_LEN - 1 ASCII characters (currently 255) satisfying [A-Za-z_.:/ -]. Additionally snapshots are allowed to contain a single @ character, while bookmarks are allowed to contain a single # character. / is used as separator between components. The maximum amount of nesting allowed in a path is zfs_max_dataset_nesting levels deep. ZFS tunables (zfs_*) are explained in zfs(4). A dataset can be one of the following: file system 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 when a block device is required. 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. See zfsconcepts(7) for details. Properties Properties are divided into two types: native properties and user-defined (or "user") properties. Native properties either export internal statistics or control ZFS behavior. In addition, native properties are filesystems and volumes. ZFS will encrypt file and zvol data, file attributes, ACLs, permission bits, directory listings, FUID mappings, and userused/groupused/projectused data. For an overview of encryption, see zfs-load-key(8). SUBCOMMANDS All subcommands that modify state are logged persistently to the pool in their original form. zfs -? Displays a help message. zfs -V, --version zfs version Displays the software version of the zfs userland utility and the zfs kernel module. Dataset Management zfs-list(8) Lists the property information for the given datasets in tabular form. zfs-create(8) Creates a new ZFS file system or volume. zfs-destroy(8) Destroys the given dataset(s), snapshot(s), or bookmark. zfs-rename(8) Renames the given dataset (filesystem or snapshot). zfs-upgrade(8) Manage upgrading the on-disk version of filesystems. Snapshots zfs-snapshot(8) Creates snapshots with the given names. zfs-rollback(8) Roll back the given dataset to a previous snapshot. zfs-hold(8)/zfs-release(8) Add or remove a hold reference to the specified snapshot or snapshots. If a hold exists on a snapshot, attempts to destroy that snapshot by using the zfs destroy command return EBUSY. zfs-diff(8) 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. Clones zfs-clone(8) Creates a clone of the given snapshot. zfs-promote(8) Promotes a clone file system to no longer be dependent on its "origin" snapshot. 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(8) subcommand, which by default creates a full stream. zfs-bookmark(8) Creates a new bookmark of the given snapshot or bookmark. Bookmarks mark the point in time when the snapshot was created, and can be used as the incremental source for a zfs send command. zfs-redact(8) Generate a new redaction bookmark. This feature can be used to allow clones of a filesystem to be made available on a remote system, in the case where their parent need not (or needs to not) be usable. Properties zfs-get(8) Displays properties for the given datasets. zfs-set(8) Sets the property or list of properties to the given value(s) for each dataset. zfs-inherit(8) 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. Quotas zfs-userspace(8)/zfs-groupspace(8)/zfs-projectspace(8) Displays space consumed by, and quotas on, each user, group, or project in the specified filesystem or snapshot. zfs-project(8) List, set, or clear project ID and/or inherit flag on the files or directories. Mountpoints zfs-mount(8) Displays all ZFS file systems currently mounted, or mount ZFS filesystem on a path described by its mountpoint property. zfs-unmount(8) Unmounts currently mounted ZFS file systems. Shares zfs-share(8) Shares available ZFS file systems. zfs-unshare(8) Unshares currently shared ZFS file systems. Delegated Administration zfs-allow(8) Delegate permissions on the specified filesystem or volume. zfs-unallow(8) Remove delegated permissions on the specified filesystem or volume. Encryption Unload a key for the specified dataset, removing the ability to access the dataset. Channel Programs zfs-program(8) Execute ZFS administrative operations programmatically via a Lua script-language channel program. Jails zfs-jail(8) Attaches a filesystem to a jail. zfs-unjail(8) Detaches a filesystem from a jail. Waiting zfs-wait(8) Wait for background activity in a filesystem to complete. 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 listsnaps=on. The default is off. See zpoolprops(7) for more information on pool properties. # zfs list 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 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 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 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@4daysago @5daysago The following commands show how to set sharenfs property options to enable read-write 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:[::1],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 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 creates a bookmark to a snapshot. This bookmark can then be used instead of a 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 a user and their 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 is required, as follows. Samba will need to bind to the loopback interface 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 (passwd(5), LDAP, smbpasswd(5), &c.). How to do this is outside the scope of this document - refer to smb.conf(5) for more information. See the USERSHARES section for all configuration options, in case you need to modify any options of the share afterwards. Do note that any changes done with the net(8) command will be undone if the share is ever unshared (like via a reboot). ENVIRONMENT VARIABLES ZFS_COLOR Use ANSI color in zfs diff and zfs list output. ZFS_MOUNT_HELPER Cause zfs mount to use mount(8) to mount ZFS datasets. This option is provided for backwards compatibility with older ZFS versions. ZFS_SET_PIPE_MAX Tells zfs to set the maximum pipe size for sends/recieves. Disabled by default on Linux due to an unfixed deadlock in Linux's pipe size handling code. SEE ALSO attr(1), gzip(1), ssh(1), chmod(2), fsync(2), stat(2), write(2), acl(5), attributes(5), exports(5), zfsconcepts(7), zfsprops(7), exportfs(8), mount(8), net(8), selinux(8), zfs-allow(8), zfs-bookmark(8), zfs-change-key(8), zfs-clone(8), zfs-create(8), zfs-destroy(8), zfs-diff(8), zfs-get(8), zfs-groupspace(8), zfs-hold(8), zfs-inherit(8), zfs-jail(8), zfs-list(8), zfs-load-key(8), zfs-mount(8), zfs-program(8), zfs-project(8), zfs-projectspace(8), zfs-promote(8), zfs-receive(8), zfs-redact(8), zfs-release(8), zfs-rename(8), zfs-rollback(8), zfs-send(8), zfs-set(8), zfs-share(8), zfs-snapshot(8), zfs-unallow(8), zfs-unjail(8), zfs-unload-key(8), zfs-unmount(8), zfs-unshare(8), zfs-upgrade(8), zfs-userspace(8), zfs-wait(8), zpool(8) FreeBSD 14.0-RELEASE-p6 May 12, 2022 FreeBSD 14.0-RELEASE-p6