mirror_zfs/man/man8/zfs.8

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.Dd June 30, 2019
.Dt ZFS 8
.Os Linux
.Sh NAME
.Nm zfs
.Nd configures ZFS file systems
.Sh SYNOPSIS
.Nm
.Fl ?V
.Nm
.Cm version
.Nm
.Cm <subcommand>
.Op Ar <args>
.Sh DESCRIPTION
The
.Nm
command configures ZFS datasets within a ZFS storage pool, as described in
.Xr zpool 8 .
A dataset is identified by a unique path within the ZFS namespace.
For example:
.Bd -literal
pool/{filesystem,volume,snapshot}
.Ed
.Pp
where the maximum length of a dataset name is
.Dv MAXNAMELEN
.Pq 256 bytes
and the maximum amount of nesting allowed in a path is 50 levels deep.
.Pp
A dataset can be one of the following:
.Bl -tag -width "file system"
.It Sy file system
A ZFS dataset of type
.Sy 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.
.It Sy 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.
.It Sy snapshot
A read-only version of a file system or volume at a given point in time.
It is specified as
.Ar filesystem Ns @ Ns Ar name
or
.Ar volume Ns @ Ns Ar name .
.It Sy bookmark
Much like a
.Sy 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
.Ar filesystem Ns # Ns Ar name
or
.Ar volume Ns # Ns Ar name .
.El
.Pp
For details see
.Xr zfsconcepts 8 .
.Ss Properties
Properties are divided into two types, native properties and user-defined
.Po or
.Qq user
.Pc
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
.Xr zfsprops 8 man page.
.Ss Encryption
Enabling the
.Sy 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
.Sy userused
/
.Sy groupused
data.
For an overview of encryption see the
.Xr zfs-load-key 8 command manual.
.Sh SUBCOMMANDS
All subcommands that modify state are logged persistently to the pool in their
original form.
.Bl -tag -width ""
.It Nm Fl ?
Displays a help message.
.It Xo
.Nm
.Fl V , -version
.Xc
An alias for the
.Nm zfs Cm version
subcommand.
.It Xo
.Nm
.Cm version
.Xc
Displays the software version of the
.Nm
userland utility and the zfs kernel module.
.El
.Ss Dataset Management
.Bl -tag -width ""
.It Xr zfs-list 8
Lists the property information for the given datasets in tabular form.
.It Xr zfs-create 8
Creates a new ZFS file system or volume.
.It Xr zfs-destroy 8
Destroys the given dataset(s), snapshot(s), or bookmark.
.It Xr zfs-rename 8
Renames the given dataset (filesystem or snapshot).
.It Xr zfs-upgrade 8
Manage upgrading the on-disk version of filesystems.
.El
.Ss Snapshots
.Bl -tag -width ""
.It Xr zfs-snapshot 8
Creates snapshots with the given names.
.It Xr zfs-rollback 8
Roll back the given dataset to a previous snapshot.
.It Xo
.Xr zfs-hold 8 /
.Xr zfs-release 8
.Xc
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
.Nm zfs Cm destroy
command return
.Er EBUSY .
.It Xr 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.
.El
.Ss Clones
.Bl -tag -width ""
.It Xr zfs-clone 8
Creates a clone of the given snapshot.
.It Xr zfs-promote 8
Promotes a clone file system to no longer be dependent on its
.Qq origin
snapshot.
.El
.Ss Send & Receive
.Bl -tag -width ""
.It Xr zfs-send 8
Generate a send stream, which may be of a filesystem, and may be incremental
from a bookmark.
.It Xr zfs-receive 8
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
.Xr zfs-send 8
subcommand, which by default creates a full stream.
.It Xr zfs-bookmark 8
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
.Nm zfs Cm send
command.
.It Xr 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.
.El
.Ss Properties
.Bl -tag -width ""
.It Xr zfs-get 8
Displays properties for the given datasets.
.It Xr zfs-set 8
Sets the property or list of properties to the given value(s) for each dataset.
.It Xr 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
.Fl S
option reverted to the received value if one exists.
.El
.Ss Quotas
.Bl -tag -width ""
.It Xo
.Xr zfs-userspace 8 /
.Xr zfs-groupspace 8 /
.Xr zfs-projectspace 8
.Xc
Displays space consumed by, and quotas on, each user, group, or project
in the specified filesystem or snapshot.
.It Xr zfs-project 8
List, set, or clear project ID and/or inherit flag on the file(s) or directories.
.El
.Ss Mountpoints
.Bl -tag -width ""
.It Xr zfs-mount 8
Displays all ZFS file systems currently mounted, or mount ZFS filesystem
on a path described by its
.Sy mountpoint
property.
.It Xr zfs-unmount 8
Unmounts currently mounted ZFS file systems.
.El
.Ss Shares
.Bl -tag -width ""
.It Xr zfs-share 8
Shares available ZFS file systems.
.It Xr zfs-unshare 8
Unshares currently shared ZFS file systems.
.El
.Ss Delegated Administration
.Bl -tag -width ""
.It Xr zfs-allow 8
Delegate permissions on the specified filesystem or volume.
.It Xr zfs-unallow 8
Remove delegated permissions on the specified filesystem or volume.
.El
.Ss Encryption
.Bl -tag -width ""
.It Xr zfs-change-key 8
Add or change an encryption key on the specified dataset.
.It Xr zfs-load-key 8
Load the key for the specified encrypted dataset, enabling access.
.It Xr zfs-unload-key 8
Unload a key for the specified dataset, removing the ability to access the dataset.
.El
.Ss Channel Programs
.Bl -tag -width ""
.It Xr zfs-program 8
Execute ZFS administrative operations
programmatically via a Lua script-language channel program.
.El
.Ss Jails
.Bl -tag -width ""
.It Xr zfs-jail 8
Attaches a filesystem to a jail.
.It Xr zfs-unjail 8
Detaches a filesystem from a jail.
.El
.Sh EXIT STATUS
The
.Nm
utility exits 0 on success, 1 if an error occurs, and 2 if invalid command line
options were specified.
.Sh EXAMPLES
.Bl -tag -width ""
.It Sy Example 1 No Creating a ZFS File System Hierarchy
The following commands create a file system named
.Em pool/home
and a file system named
.Em pool/home/bob .
The mount point
.Pa /export/home
is set for the parent file system, and is automatically inherited by the child
file system.
.Bd -literal
# zfs create pool/home
# zfs set mountpoint=/export/home pool/home
# zfs create pool/home/bob
.Ed
.It Sy Example 2 No Creating a ZFS Snapshot
The following command creates a snapshot named
.Sy yesterday .
This snapshot is mounted on demand in the
.Pa .zfs/snapshot
directory at the root of the
.Em pool/home/bob
file system.
.Bd -literal
# zfs snapshot pool/home/bob@yesterday
.Ed
.It Sy Example 3 No Creating and Destroying Multiple Snapshots
The following command creates snapshots named
.Sy yesterday
of
.Em pool/home
and all of its descendent file systems.
Each snapshot is mounted on demand in the
.Pa .zfs/snapshot
directory at the root of its file system.
The second command destroys the newly created snapshots.
.Bd -literal
# zfs snapshot -r pool/home@yesterday
# zfs destroy -r pool/home@yesterday
.Ed
.It Sy Example 4 No Disabling and Enabling File System Compression
The following command disables the
.Sy compression
property for all file systems under
.Em pool/home .
The next command explicitly enables
.Sy compression
for
.Em pool/home/anne .
.Bd -literal
# zfs set compression=off pool/home
# zfs set compression=on pool/home/anne
.Ed
.It Sy Example 5 No Listing ZFS Datasets
The following command lists all active file systems and volumes in the system.
Snapshots are displayed if the
.Sy listsnaps
property is
.Sy on .
The default is
.Sy off .
See
.Xr zpool 8
for more information on pool properties.
.Bd -literal
# 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
.Ed
.It Sy Example 6 No Setting a Quota on a ZFS File System
The following command sets a quota of 50 Gbytes for
.Em pool/home/bob .
.Bd -literal
# zfs set quota=50G pool/home/bob
.Ed
.It Sy Example 7 No Listing ZFS Properties
The following command lists all properties for
.Em pool/home/bob .
.Bd -literal
# 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                      -
.Ed
.Pp
The following command gets a single property value.
.Bd -literal
# zfs get -H -o value compression pool/home/bob
on
.Ed
The following command lists all properties with local settings for
.Em pool/home/bob .
.Bd -literal
# 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
.Ed
.It Sy Example 8 No Rolling Back a ZFS File System
The following command reverts the contents of
.Em pool/home/anne
to the snapshot named
.Sy yesterday ,
deleting all intermediate snapshots.
.Bd -literal
# zfs rollback -r pool/home/anne@yesterday
.Ed
.It Sy Example 9 No Creating a ZFS Clone
The following command creates a writable file system whose initial contents are
the same as
.Em pool/home/bob@yesterday .
.Bd -literal
# zfs clone pool/home/bob@yesterday pool/clone
.Ed
.It Sy Example 10 No 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:
.Bd -literal
# 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
.Ed
.It Sy Example 11 No Inheriting ZFS Properties
The following command causes
.Em pool/home/bob
and
.Em pool/home/anne
to inherit the
.Sy checksum
property from their parent.
.Bd -literal
# zfs inherit checksum pool/home/bob pool/home/anne
.Ed
.It Sy Example 12 No Remotely Replicating ZFS Data
The following commands send a full stream and then an incremental stream to a
remote machine, restoring them into
.Em poolB/received/fs@a
and
.Em poolB/received/fs@b ,
respectively.
.Em poolB
must contain the file system
.Em poolB/received ,
and must not initially contain
.Em poolB/received/fs .
.Bd -literal
# zfs send pool/fs@a | \e
  ssh host zfs receive poolB/received/fs@a
# zfs send -i a pool/fs@b | \e
  ssh host zfs receive poolB/received/fs
.Ed
.It Sy Example 13 No Using the zfs receive -d Option
The following command sends a full stream of
.Em poolA/fsA/fsB@snap
to a remote machine, receiving it into
.Em poolB/received/fsA/fsB@snap .
The
.Em fsA/fsB@snap
portion of the received snapshot's name is determined from the name of the sent
snapshot.
.Em poolB
must contain the file system
.Em poolB/received .
If
.Em poolB/received/fsA
does not exist, it is created as an empty file system.
.Bd -literal
# zfs send poolA/fsA/fsB@snap | \e
  ssh host zfs receive -d poolB/received
.Ed
.It Sy Example 14 No Setting User Properties
The following example sets the user-defined
.Sy com.example:department
property for a dataset.
.Bd -literal
# zfs set com.example:department=12345 tank/accounting
.Ed
.It Sy Example 15 No 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:
.Bd -literal
# 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
.Ed
.It Sy Example 16 No Setting sharenfs Property Options on a ZFS File System
The following commands show how to set
.Sy sharenfs
property options to enable
.Sy rw
access for a set of
.Sy IP
addresses and to enable root access for system
.Sy neo
on the
.Em tank/home
file system.
.Bd -literal
# zfs set sharenfs='rw=@123.123.0.0/16,root=neo' tank/home
.Ed
.Pp
If you are using
.Sy DNS
for host name resolution, specify the fully qualified hostname.
.It Sy Example 17 No Delegating ZFS Administration Permissions on a ZFS Dataset
The following example shows how to set permissions so that user
.Sy cindys
can create, destroy, mount, and take snapshots on
.Em tank/cindys .
The permissions on
.Em tank/cindys
are also displayed.
.Bd -literal
# 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
.Ed
.Pp
Because the
.Em tank/cindys
mount point permission is set to 755 by default, user
.Sy cindys
will be unable to mount file systems under
.Em tank/cindys .
Add an ACE similar to the following syntax to provide mount point access:
.Bd -literal
# chmod A+user:cindys:add_subdirectory:allow /tank/cindys
.Ed
.It Sy Example 18 No Delegating Create Time Permissions on a ZFS Dataset
The following example shows how to grant anyone in the group
.Sy staff
to create file systems in
.Em 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
.Em tank/users
are also displayed.
.Bd -literal
# 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
.Ed
.It Sy Example 19 No Defining and Granting a Permission Set on a ZFS Dataset
The following example shows how to define and grant a permission set on the
.Em tank/users
file system.
The permissions on
.Em tank/users
are also displayed.
.Bd -literal
# 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
.Ed
.It Sy Example 20 No Delegating Property Permissions on a ZFS Dataset
The following example shows to grant the ability to set quotas and reservations
on the
.Em users/home
file system.
The permissions on
.Em users/home
are also displayed.
.Bd -literal
# 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
.Ed
.It Sy Example 21 No Removing ZFS Delegated Permissions on a ZFS Dataset
The following example shows how to remove the snapshot permission from the
.Sy staff
group on the
.Em tank/users
file system.
The permissions on
.Em tank/users
are also displayed.
.Bd -literal
# 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
.Ed
.It Sy Example 22 No 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
.Fl F
option is used to indicate type information for the files affected.
.Bd -literal
# 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
.Ed
.It Sy Example 23 No Creating a bookmark
The following example create a bookmark to a snapshot.
This bookmark can then be used instead of snapshot in send streams.
.Bd -literal
# zfs bookmark rpool@snapshot rpool#bookmark
.Ed
.It Sy Example 24 No 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.
.Bd -literal
# smbmount //127.0.0.1/share_tmp /mnt/tmp \\
  -o user=workgroup/turbo,password=obrut,uid=1000
.Ed
.Pp
Minimal
.Em /etc/samba/smb.conf
configuration required:
.Pp
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.
.Pp
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
.Xr smb.conf 5
man page for more information.
.Pp
See the
.Sy USERSHARE section
of the
.Xr 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
.Xr net 8
command will be undone if the share is ever unshared (such as at a reboot etc).
.El
.Sh INTERFACE STABILITY
.Sy Committed .
.Sh SEE ALSO
.Xr attr 1 ,
.Xr gzip 1 ,
.Xr ssh 1 ,
.Xr chmod 2 ,
.Xr fsync 2 ,
.Xr stat 2 ,
.Xr write 2 ,
.Xr acl 5 ,
.Xr attributes 5 ,
.Xr exports 5 ,
.Xr exportfs 8 ,
.Xr mount 8 ,
.Xr net 8 ,
.Xr selinux 8 ,
.Xr zfsconcepts 8 ,
.Xr zfsprops 8 ,
.Xr zpool 8