|ZFS(8)||System Manager's Manual||ZFS(8)|
zfs — configures
ZFS file systems
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
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 non-standard behavior when checking file system free space.
- 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.
- 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.
- 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.
For details see zfsconcepts(8).
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 either editable or read-only. User properties have no effect on ZFS behavior, but you can use them to annotate datasets in a way that is meaningful in your environment. For more information about properties, see the zfsprops(8) man page.
Enabling the encryption feature allows for the creation of encrypted filesystems and volumes. ZFS will encrypt file and zvol data, file attributes, ACLs, permission bits, directory listings, FUID mappings, and userused / groupused data. For an overview of encryption see the zfs-load-key(8) command manual.
All subcommands that modify state are logged persistently to the pool in their original form.
- Displays a help message.
- An alias for the
- Displays the software version of the
zfsuserland utility and the zfs kernel module.
- Lists the property information for the given datasets in tabular form.
- Creates a new ZFS file system or volume.
- Destroys the given dataset(s), snapshot(s), or bookmark.
- Renames the given dataset (filesystem or snapshot).
- Manage upgrading the on-disk version of filesystems.
- Creates snapshots with the given names.
- 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
- 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.
Send & Receive¶
- Generate a send stream, which may be of a filesystem, and may be incremental from a bookmark.
- 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(8) subcommand, which by default creates a full stream.
- 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
- 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.
- Displays properties for the given datasets.
- Sets the property or list of properties to the given value(s) for each dataset.
- Clears the specified property, causing it to be inherited from an
ancestor, restored to default if no ancestor has the property set, or with
-Soption reverted to the received value if one exists.
- Execute ZFS administrative operations programmatically via a Lua script-language channel program.
- Wait for background activity in a filesystem to complete.
zfs utility exits 0 on success, 1 if
an error occurs, and 2 if invalid command line options were specified.
- 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
# 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
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
# zfs set quota=50G pool/home/bob
- Example 7 Listing ZFS Properties
- The following command lists all properties for
# 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
# 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
# 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
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
respectively. poolB must contain the file system
poolB/received, and must not initially contain
# 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
to a remote machine, receiving it into
portion of the received snapshot's name is determined from the name of the
sent snapshot. poolB must contain the file system
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
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 commands show how to set
property options to enable
for a set of
and to enable root access for system
neo on the
# zfs set firstname.lastname@example.org/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
# 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
-Foption 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).
attr(1), gzip(1), ssh(1), chmod(2), fsync(2), stat(2), write(2), acl(5), attributes(5), exports(5), 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), zfsconcepts(8), zfsprops(8), zpool(8)
|June 30, 2019||Linux|