Manual browser: zfs(8)
|zfs(1M)||System Administration Commands||zfs(1M)|
NAMEzfs - configures ZFS file systems
zfs create [[-o property=value]]... filesystem
zfs create [-s] [-b blocksize] [[-o property=value]]... -V size volume
zfs destroy [-rRf] filesystem|volume|snapshot
zfs clone snapshot filesystem|volume
zfs promote filesystem
zfs rename filesystem|volume|snapshot
zfs snapshot [-r] filesystem@name|volume@name
zfs rollback [-rRf] snapshot
zfs list [-rH] [-o prop[,prop] ]... [ -t type[,type]...]
[ -s prop [-s prop]... [ -S prop [-S prop]...
zfs set property=value filesystem|volume ...
zfs get [-rHp] [-o field[,field]...]
[-s source[,source]...] all | property[,property]...
zfs inherit [-r] property filesystem|volume... ...
zfs mount [-o options] [-O] -a
zfs mount [-o options] [-O] filesystem
zfs unmount [-f] -a
zfs unmount [-f] filesystem|mountpoint
zfs share -a
zfs share filesystem
zfs unshare [-f] -a
zfs unshare [-f] filesystem|mountpoint
zfs send [-i snapshot1] snapshot2
zfs receive [-vnF ] filesystem|volume|snapshot
zfs receive [-vnF ] -d filesystem
zfs jail jailid filesystem
zfs unjail jailid filesystem
DESCRIPTIONThe zfs command configures ZFS datasets within a ZFS storage pool, as described in zpool(1M). 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).
A dataset can be one of the following:
ZFS File System HierarchyA ZFS storage pool is a logical collection of devices that provide space for datasets. A storage pool is also the root of the ZFS file system hierarchy.
The root of the pool can be accessed as a file system, such as mounting and unmounting, taking snapshots, and setting properties. The physical storage characteristics, however, are managed by the zpool(1M) command.
See zpool(1M) for more information on creating and administering pools.
SnapshotsA snapshot is a read-only copy of a file system or volume. Snapshots can be created extremely quickly, and initially consume no additional space within the pool. As data within the active dataset changes, the snapshot consumes more data than would otherwise be shared with the active dataset.
Snapshots can have arbitrary names. Snapshots of volumes can be cloned or rolled back, but cannot be accessed independently.
File system snapshots can be accessed under the ".zfs/snapshot" directory in the root of the file system. Snapshots are automatically mounted on demand and may be unmounted at regular intervals. The visibility of the ".zfs" directory can be controlled by the "snapdir" property.
ClonesA clone is a writable volume or file system whose initial contents are the same as another dataset. As with snapshots, creating a clone is nearly instantaneous, and initially consumes no additional space.
Clones can only be created from a snapshot. When a snapshot is cloned, it creates an implicit dependency between the parent and child. Even though the clone is created somewhere else in the dataset hierarchy, the original snapshot cannot be destroyed as long as a clone exists. The "origin" property exposes this dependency, and the destroy command lists any such dependencies, if they exist.
The clone parent-child dependency relationship can be reversed by using the "promote" subcommand. This causes the "origin" file system to become a clone of the specified file system, which makes it possible to destroy the file system that the clone was created from.
Mount PointsCreating a ZFS file system is a simple operation, so the number of file systems per system will likely be numerous. To cope with this, ZFS automatically manages mounting and unmounting file systems without the need to edit the /etc/vfstab file. All automatically managed file systems are mounted by ZFS at boot time.
By default, file systems are mounted under /path, where path is the name of the file system in the ZFS namespace. Directories are created and destroyed as needed.
A file system can also have a mount point set in the "mountpoint" property. This directory is created as needed, and ZFS automatically mounts the file system when the "zfs mount -a" command is invoked (without editing /etc/vfstab). The mountpoint property can be inherited, so if pool/home has a mount point of /export/stuff, then pool/home/user automatically inherits a mount point of /export/stuff/user.
A file system mountpoint property of "none" prevents the file system from being mounted.
If needed, ZFS file systems can also be managed with traditional tools (mount, umount, /etc/vfstab). If a file system's mount point is set to "legacy", ZFS makes no attempt to manage the file system, and the administrator is responsible for mounting and unmounting the file system.
ZonesA ZFS file system can be added to a non-global zone by using zonecfg's "add fs" subcommand. A ZFS file system that is added to a non-global zone must have its mountpoint property set to legacy.
The physical properties of an added file system are controlled by the global administrator. However, the zone administrator can create, modify, or destroy files within the added file system, depending on how the file system is mounted.
A dataset can also be delegated to a non-global zone by using zonecfg's "add dataset" subcommand. You cannot delegate a dataset to one zone and the children of the same dataset to another zone. The zone administrator can change properties of the dataset or any of its children. However, the "quota" property is controlled by the global administrator.
A ZFS volume can be added as a device to a non-global zone by using zonecfg's "add device" subcommand. However, its physical properties can only be modified by the global administrator.
For more information about zonecfg syntax, see zonecfg(1M).
After a dataset is delegated to a non-global zone, the "zoned" property is automatically set. A zoned file system cannot be mounted in the global zone, since the zone administrator might have to set the mount point to an unacceptable value.
The global administrator can forcibly clear the "zoned" property, though this should be done with extreme care. The global administrator should verify that all the mount points are acceptable before clearing the property.
Native PropertiesProperties are divided into two types, native properties and user defined 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 user properties, see the "User Properties" section.
Every dataset has a set of properties that export statistics about the dataset as well as control various behavior. Properties are inherited from the parent unless overridden by the child. Snapshot properties can not be edited; they always inherit their inheritable properties. Properties that are not applicable to snapshots are not displayed.
The values of numeric properties can be specified using the following human-readable suffixes (for example, "k", "KB", "M", "Gb", etc, up to Z for zettabyte). The following are all valid (and equal) specifications:
"1536M", "1.5g", "1.50GB".
The values of non-numeric properties are case sensitive and must be lowercase, except for "mountpoint" and "sharenfs".
The first set of properties consist of read-only statistics about the dataset. These properties cannot be set, nor are they inherited. Native properties apply to all dataset types unless otherwise noted.
The following two properties can be set to control the way space is allocated between datasets. These properties are not inherited, but do affect their descendants.
iscsioptionsThis read-only property, which is hidden, is used by the iSCSI target daemon to store persistent information, such as the IQN. It cannot be viewed or modified using the zfs command. The contents are not intended for external consumers.
Temporary Mount Point PropertiesWhen a file system is mounted, either through mount(1M) for legacy mounts or the "zfs mount" command for normal file systems, its mount options are set according to its properties. The correlation between properties and mount options is as follows:
PROPERTY MOUNT OPTION
In addition, these options can be set on a per-mount basis using the -o option, without affecting the property that is stored on disk. The values specified on the command line override the values stored in the dataset. The -nosuid option is an alias for "nodevices,nosetuid". These properties are reported as "temporary" by the " zfs get" command. If the properties are changed while the dataset is mounted, the new setting overrides any temporary settings.
User PropertiesIn addition to the standard native properties, ZFS supports arbitrary user properties. User properties have no effect on ZFS behavior, but applications or administrators can use them to annotate datasets.
User property names must contain a colon (":") character, to distinguish them from native properties. They might contain lowercase letters, numbers, and the following punctuation characters: colon (":"), dash ("-"), period ("."), and underscore ("_"). The expected convention is that the property name is divided into two portions such as " module:property", but this namespace is not enforced by ZFS. User property names can be at most 256 characters, and cannot begin with a dash ("-").
When making programmatic use of user properties, it is strongly suggested to use a reversed DNS domain name for the module component of property names to reduce the chance that two independently-developed packages use the same property name for different purposes. Property names beginning with "com.sun." are reserved for use by Sun Microsystems.
The values of user properties are arbitrary strings, are always inherited, and are never validated. All of the commands that operate on properties ("zfs list", "zfs get", "zfs set", etc.) can be used to manipulate both native properties and user properties. Use the " zfs inherit" command to clear a user property . If the property is not defined in any parent dataset, it is removed entirely. Property values are limited to 1024 characters.
Volumes as Swap or Dump DevicesTo set up a swap area, create a ZFS volume of a specific size and then enable swap on that device. For more information, see the EXAMPLES section.
Do not swap to a file on a ZFS file system. A ZFS swap file configuration is not supported.
Using a ZFS volume as a dump device is not supported.
SUBCOMMANDSAll subcommands that modify state are logged persistently to the pool in their original form.
- 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.
name Dataset name
property Property name
value Property value
source Property source. Can either be local, default,
temporary, inherited, or none (-).
The format of the stream is evolving. No backwards compatibility is guaranteed. You may not be able to receive your streams on future versions of ZFS.
EXAMPLESExample 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 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 Taking and destroying multiple snapshots
The following command creates snapshots named "yesterday" of "pool/home" and all of its descendant 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 Turning Off Compression
The following commands turn compression off for all file systems under "pool/home", but explicitly turns it on 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.
# zfs list
NAME USED AVAIL REFER MOUNTPOINT
pool 100G 60G - /pool
pool/home 100G 60G - /export/home
pool/home/bob 40G 60G 40G /export/home/bob
pool/home/bob@yesterday 3M - 40G -
pool/home/anne 60G 60G 40G /export/home/anne
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 Fri Feb 23 14:20 2007 -
pool/home/bob used 24.5K -
pool/home/bob available 50.0G -
pool/home/bob referenced 24.5K -
pool/home/bob compressratio 1.00x -
pool/home/bob mounted yes -
pool/home/bob quota 50G 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 shareiscsi off default
pool/home/bob checksum on default
pool/home/bob compression off default
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 aclmode groupmask default
pool/home/bob aclinherit secure default
pool/home/bob canmount on default
pool/home/bob xattr on default
The following command gets a single property value.
# zfs get -H -o value compression pool/home/bob
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 compression on
pool/home checksum off
Example 8 Rolling Back a ZFS File System
The following command reverts the contents of "pool/home/anne" to the snapshot named "yesterday", deleting all intermediate snapshots.
# zfs rollback -r pool/home/anne@yesterday
Example 9 Creating a ZFS Clone
The following command creates a writable file system whose initial contents are the same as "pool/home/bob@yesterday".
# zfs clone pool/home/bob@yesterday pool/clone
Example 10 Promoting a ZFS Clone
The following commands illustrate how to test out changes to a file system, and then replace the original file system with the changed one, using clones, clone promotion, and renaming:
# zfs create pool/project/production
populate /pool/project/production with data
# zfs snapshot pool/project/production@today
# zfs clone pool/project/production@today pool/project/beta
make changes to /pool/project/beta and test them
# zfs promote pool/project/beta
# zfs rename pool/project/production pool/project/legacy
# zfs rename pool/project/beta pool/project/production
once the legacy version is no longer needed, it can be
# 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 will be created as an empty file system.
# zfs send poolA/fsA/fsB@snap | \
ssh host zfs receive -d poolB/received
Example 14 Creating a ZFS volume as a Swap Device
The following example shows how to create a 5-Gbyte ZFS volume and then add the volume as a swap device.
# zfs create -V 5gb tank/vol
# swap -a /dev/zvol/dsk/tank/vol
Example 15 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 16 Creating a ZFS Volume as a iSCSI Target Device
The following example shows how to create a ZFS volume as an iSCSI target.
# zfs create -V 2g pool/volumes/vol1
# zfs set shareiscsi=on pool/volumes/vol1
# iscsitadm list target
After the iSCSI target is created, set up the iSCSI initiator. For more information about the Solaris iSCSI initiator, see the Solaris Administration Guide: Devices and File Systems.
EXIT STATUSThe following exit values are returned:
ATTRIBUTESSee attributes(5) for descriptions of the following attributes:
SEE ALSOgzip(1), ssh(1), mount(1M), share(1M), unshare(1M), zonecfg(1M), zpool(1M), chmod(2), stat(2), fsync(3c), dfstab(4), attributes(5)
|16 Mar 2007||SunOS 5.11|