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zpool(1M)               System Administration Commands               zpool(1M)



NAME
       zpool - configures ZFS storage pools

SYNOPSIS
       zpool [-?]


       zpool create [-fn] [-R root] [-m mountpoint] pool vdev ...


       zpool destroy [-f] pool


       zpool add [-fn] pool vdev


       zpool remove pool vdev


       zpool  list [-H] [-o field[,field]*] [pool] ...


       zpool iostat [-v] [pool] ... [interval [count]]


       zpool status [-xv] [pool] ...


       zpool offline [-t] pool device ...


       zpool online pool device ...


       zpool clear pool [device] ...


       zpool attach [-f] pool device new_device


       zpool detach pool device


       zpool replace [-f] pool device [new_device]


       zpool scrub [-s] pool ...


       zpool export [-f] pool


       zpool import [-d dir] [-D]


       zpool import [-d dir] [-D] [-f] [-o opts] [-R root] pool | id
           [newpool]


       zpool import [-d dir] [-D] [-f] [-a]


       zpool upgrade


       zpool upgrade -v


       zpool upgrade [-a | pool]


       zpool history [pool] ...


DESCRIPTION
       The zpool command configures ZFS storage pools. A storage pool is a
       collection of devices that provides physical storage and data
       replication for ZFS datasets.

       All datasets within a storage pool share the same space. See zfs(1M)
       for information on managing datasets.

   Virtual Devices (vdevs)
       A "virtual device" describes a single device or a collection of devices
       organized according to certain performance and fault characteristics.
       The following virtual devices are supported:

       disk
                 A block device, typically located under "/dev/dsk". ZFS can
                 use individual slices or partitions, though the recommended
                 mode of operation is to use whole disks. A disk can be
                 specified by a full path, or it can be a shorthand name (the
                 relative portion of the path under "/dev/dsk"). A whole disk
                 can be specified by omitting the slice or partition
                 designation. For example, "c0t0d0" is equivalent to
                 "/dev/dsk/c0t0d0s2". When given a whole disk, ZFS
                 automatically labels the disk, if necessary.


       file
                 A regular file. The use of files as a backing store is
                 strongly discouraged. It is designed primarily for
                 experimental purposes, as the fault tolerance of a file is
                 only as good as the file system of which it is a part. A file
                 must be specified by a full path.


       mirror
                 A mirror of two or more devices. Data is replicated in an
                 identical fashion across all components of a mirror. A mirror
                 with N disks of size X can hold X bytes and can withstand
                 (N-1) devices failing before data integrity is compromised.


       raidz
       raidz1
       raidz2
                 A variation on RAID-5 that allows for better distribution of
                 parity and eliminates the "RAID-5 write hole" (in which data
                 and parity become inconsistent after a power loss). Data and
                 parity is striped across all disks within a raidz group.

                 A raidz group can have either single- or double-parity,
                 meaning that the raidz group can sustain one or two failures
                 respectively without losing any data. The raidz1 vdev type
                 specifies a single-parity raidz group and the raidz2 vdev
                 type specifies a double-parity raidz group. The raidz vdev
                 type is an alias for raidz1.

                 A raidz group with N disks of size X with P parity disks can
                 hold approximately (N-P)*X bytes and can withstand one device
                 failing before data integrity is compromised. The minimum
                 number of devices in a raidz group is one more than the
                 number of parity disks. The recommended number is between 3
                 and 9.


       spare
                 A special pseudo-vdev which keeps track of available hot
                 spares for a pool. For more information, see the "Hot Spares"
                 section.


       Virtual devices cannot be nested, so a mirror or raidz virtual device
       can only contain files or disks. Mirrors of mirrors (or other
       combinations) are not allowed.

       A pool can have any number of virtual devices at the top of the
       configuration (known as "root vdevs"). Data is dynamically distributed
       across all top-level devices to balance data among devices. As new
       virtual devices are added, ZFS automatically places data on the newly
       available devices.

       Virtual devices are specified one at a time on the command line,
       separated by whitespace. The keywords "mirror" and "raidz" are used to
       distinguish where a group ends and another begins. For example, the
       following creates two root vdevs, each a mirror of two disks:

         # zpool create mypool mirror c0t0d0 c0t1d0 mirror c1t0d0 c1t1d0



   Device Failure and Recovery
       ZFS supports a rich set of mechanisms for handling device failure and
       data corruption. All metadata and data is checksummed, and ZFS
       automatically repairs bad data from a good copy when corruption is
       detected.

       In order to take advantage of these features, a pool must make use of
       some form of redundancy, using either mirrored or raidz groups. While
       ZFS supports running in a non-redundant configuration, where each root
       vdev is simply a disk or file, this is strongly discouraged. A single
       case of bit corruption can render some or all of your data unavailable.

       A pool's health status is described by one of three states: online,
       degraded, or faulted. An online pool has all devices operating
       normally. A degraded pool is one in which one or more devices have
       failed, but the data is still available due to a redundant
       configuration. A faulted pool has one or more failed devices, and there
       is insufficient redundancy to replicate the missing data.

   Hot Spares
       ZFS allows devices to be associated with pools as "hot spares". These
       devices are not actively used in the pool, but when an active device
       fails, it is automatically replaced by a hot spare. To create a pool
       with hot spares, specify a "spare" vdev with any number of devices. For
       example,

         # zpool create pool mirror c0d0 c1d0 spare c2d0 c3d0



       Spares can be shared across multiple pools, and can be added with the
       "zpool add" command and removed with the "zpool remove" command. Once a
       spare replacement is initiated, a new "spare" vdev is created within
       the configuration that will remain there until the original device is
       replaced. At this point, the hot spare becomes available again if
       another device fails.

       An in-progress spare replacement can be cancelled by detaching the hot
       spare. If the original faulted device is detached, then the hot spare
       assumes its place in the configuration, and is removed from the spare
       list of all active pools.

   Alternate Root Pools
       The "zpool create -R" and "zpool import -R" commands allow users to
       create and import a pool with a different root path. By default,
       whenever a pool is created or imported on a system, it is permanently
       added so that it is available whenever the system boots. For removable
       media, or when in recovery situations, this may not always be
       desirable. An alternate root pool does not persist on the system.
       Instead, it exists only until exported or the system is rebooted, at
       which point it will have to be imported again.

       In addition, all mount points in the pool are prefixed with the given
       root, so a pool can be constrained to a particular area of the file
       system. This is most useful when importing unknown pools from removable
       media, as the mount points of any file systems cannot be trusted.

       When creating an alternate root pool, the default mount point is "/",
       rather than the normal default "/pool".

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

       The zpool command provides subcommands to create and destroy storage
       pools, add capacity to storage pools, and provide information about the
       storage pools. The following subcommands are supported:

       zpool -?
           Displays a help message.


       zpool create [-fn] [-R root] [-m mountpoint] pool vdev ...
           Creates a new storage pool containing the virtual devices specified
           on the command line. The pool name must begin with a letter, and
           can only contain alphanumeric characters as well as underscore
           ("_"), dash ("-"), and period ("."). The pool names "mirror",
           "raidz", and "spare" are reserved, as are names beginning with the
           pattern "c[0-9]". The vdev specification is described in the
           "Virtual Devices" section.

           The command verifies that each device specified is accessible and
           not currently in use by another subsystem. There are some uses,
           such as being currently mounted, or specified as the dedicated dump
           device, that prevents a device from ever being used by ZFS. Other
           uses, such as having a preexisting UFS file system, can be
           overridden with the -f option.

           The command also checks that the replication strategy for the pool
           is consistent. An attempt to combine redundant and non-redundant
           storage in a single pool, or to mix disks and files, results in an
           error unless -f is specified. The use of differently sized devices
           within a single raidz or mirror group is also flagged as an error
           unless -f is specified.

           Unless the -R option is specified, the default mount point is
           "/pool". The mount point must not exist or must be empty, or else
           the root dataset cannot be mounted. This can be overridden with the
           -m option.

           -f
                            Forces use of vdevs, even if they appear in use or
                            specify a conflicting replication level. Not all
                            devices can be overridden in this manner.


           -n
                            Displays the configuration that would be used
                            without actually creating the pool. The actual
                            pool creation can still fail due to insufficient
                            privileges or device sharing.


           -R root
                            Creates the pool with an alternate root. See the
                            "Alternate Root Pools" section. The root dataset
                            has its mount point set to "/" as part of this
                            operation.


           -m mountpoint
                            Sets the mount point for the root dataset. The
                            default mount point is "/pool". The mount point
                            must be an absolute path, "legacy", or "none". For
                            more information on dataset mount points, see
                            zfs(1M).



       zpool destroy [-f] pool
           Destroys the given pool, freeing up any devices for other use. This
           command tries to unmount any active datasets before destroying the
           pool.

           -f
                 Forces any active datasets contained within the pool to be
                 unmounted.



       zpool add [-fn] pool vdev ...
           Adds the specified virtual devices to the given pool. The vdev
           specification is described in the "Virtual Devices" section. The
           behavior of the -f option, and the device checks performed are
           described in the "zpool create" subcommand.

           -f
                 Forces use of vdevs, even if they appear in use or specify a
                 conflicting replication level. Not all devices can be
                 overridden in this manner.


           -n
                 Displays the configuration that would be used without
                 actually adding the vdevs. The actual pool creation can still
                 fail due to insufficient privileges or device sharing.

           Do not add a disk that is currently configured as a quorum device
           to a zpool. Once a disk is in a zpool, that disk can then be
           configured as a quorum device.


       zpool remove pool vdev
           Removes the given vdev from the pool. This command currently only
           supports removing hot spares. Devices which are part of a mirror
           can be removed using the "zpool detach" command. Raidz and top-
           level vdevs cannot be removed from a pool.


       zpool list [-H] [-o field[,field*]] [pool] ...
           Lists the given pools along with a health status and space usage.
           When given no arguments, all pools in the system are listed.

           -H
                       Scripted mode. Do not display headers, and separate
                       fields by a single tab instead of arbitrary space.


           -o field
                       Comma-separated list of fields to display. Each field
                       must be one of:

                         name            Pool name
                         size            Total size
                         used            Amount of space used
                         available       Amount of space available
                         capacity        Percentage of pool space used
                         health          Health status


                       The default is all fields.

           This command reports actual physical space available to the storage
           pool. The physical space can be different from the total amount of
           space that any contained datasets can actually use. The amount of
           space used in a raidz configuration depends on the characteristics
           of the data being written. In addition, ZFS reserves some space for
           internal accounting that the zfs(1M) command takes into account,
           but the zpool command does not. For non-full pools of a reasonable
           size, these effects should be invisible. For small pools, or pools
           that are close to being completely full, these discrepancies may
           become more noticeable.


       zpool iostat [-v] [pool] ... [interval [count]]
           Displays I/O statistics for the given pools. When given an
           interval, the statistics are printed every interval seconds until
           Ctrl-C is pressed. If no pools are specified, statistics for every
           pool in the system is shown. If count is specified, the command
           exits after count reports are printed.

           -v
                 Verbose statistics. Reports usage statistics for individual
                 vdevs within the pool, in addition to the pool-wide
                 statistics.



       zpool status [-xv] [pool] ...
           Displays the detailed health status for the given pools. If no pool
           is specified, then the status of each pool in the system is
           displayed.

           If a scrub or resilver is in progress, this command reports the
           percentage done and the estimated time to completion. Both of these
           are only approximate, because the amount of data in the pool and
           the other workloads on the system can change.

           -x
                 Only display status for pools that are exhibiting errors or
                 are otherwise unavailable.


           -v
                 Displays verbose data error information, printing out a
                 complete list of all data errors since the last complete pool
                 scrub.



       zpool offline [-t] pool device ...
           Takes the specified physical device offline. While the device is
           offline, no attempt is made to read or write to the device.

           This command is not applicable to spares.

           -t
                 Temporary. Upon reboot, the specified physical device reverts
                 to its previous state.



       zpool online pool device ...
           Brings the specified physical device online.

           This command is not applicable to spares.


       zpool clear pool [device] ...
           Clears device errors in a pool. If no arguments are specified, all
           device errors within the pool are cleared. If one or more devices
           is specified, only those errors associated with the specified
           device or devices are cleared.


       zpool attach [-f] pool device new_device
           Attaches new_device to an existing zpool device. The existing
           device cannot be part of a raidz configuration. If device is not
           currently part of a mirrored configuration, device automatically
           transforms into a two-way mirror of device and new_device. If
           device is part of a two-way mirror, attaching new_device creates a
           three-way mirror, and so on. In either case, new_device begins to
           resilver immediately.

           -f
                 Forces use of new_device, even if its appears to be in use.
                 Not all devices can be overridden in this manner.



       zpool detach pool device
           Detaches device from a mirror. The operation is refused if there
           are no other valid replicas of the data.


       zpool replace [-f] pool old_device [new_device]
           Replaces old_device with new_device. This is equivalent to
           attaching new_device, waiting for it to resilver, and then
           detaching old_device.

           The size of new_device must be greater than or equal to the minimum
           size of all the devices in a mirror or raidz configuration.

           If new_device is not specified, it defaults to old_device. This
           form of replacement is useful after an existing disk has failed and
           has been physically replaced. In this case, the new disk may have
           the same /dev/dsk path as the old device, even though it is
           actually a different disk. ZFS recognizes this.

           -f
                 Forces use of new_device, even if its appears to be in use.
                 Not all devices can be overridden in this manner.



       zpool scrub [-s] pool ...
           Begins a scrub. The scrub examines all data in the specified pools
           to verify that it checksums correctly. For replicated (mirror or
           raidz) devices, ZFS automatically repairs any damage discovered
           during the scrub. The "zpool status" command reports the progress
           of the scrub and summarizes the results of the scrub upon
           completion.

           Scrubbing and resilvering are very similar operations. The
           difference is that resilvering only examines data that ZFS knows to
           be out of date (for example, when attaching a new device to a
           mirror or replacing an existing device), whereas scrubbing examines
           all data to discover silent errors due to hardware faults or disk
           failure.

           Because scrubbing and resilvering are I/O-intensive operations, ZFS
           only allows one at a time. If a scrub is already in progress, the
           "zpool scrub" command terminates it and starts a new scrub. If a
           resilver is in progress, ZFS does not allow a scrub to be started
           until the resilver completes.

           -s
                 Stop scrubbing.



       zpool export [-f] pool ...
           Exports the given pools from the system. All devices are marked as
           exported, but are still considered in use by other subsystems. The
           devices can be moved between systems (even those of different
           endianness) and imported as long as a sufficient number of devices
           are present.

           Before exporting the pool, all datasets within the pool are
           unmounted.

           For pools to be portable, you must give the zpool command whole
           disks, not just slices, so that ZFS can label the disks with
           portable EFI labels. Otherwise, disk drivers on platforms of
           different endianness will not recognize the disks.

           -f
                 Forcefully unmount all datasets, using the "unmount -f"
                 command.



       zpool import [-d dir] [-D]
           Lists pools available to import. If the -d option is not specified,
           this command searches for devices in "/dev/dsk". The -d option can
           be specified multiple times, and all directories are searched. If
           the device appears to be part of an exported pool, this command
           displays a summary of the pool with the name of the pool, a numeric
           identifier, as well as the vdev layout and current health of the
           device for each device or file. Destroyed pools, pools that were
           previously destroyed with the "-zpool destroy" command, are not
           listed unless the -D option is specified.

           The numeric identifier is unique, and can be used instead of the
           pool name when multiple exported pools of the same name are
           available.

           -d dir
                     Searches for devices or files in dir. The -d option can
                     be specified multiple times.


           -D
                     Lists destroyed pools only.



       zpool import [-d dir] [-D] [-f] [-o opts] [-R root] pool | id [newpool]
           Imports a specific pool. A pool can be identified by its name or
           the numeric identifier. If newpool is specified, the pool is
           imported using the name newpool. Otherwise, it is imported with the
           same name as its exported name.

           If a device is removed from a system without running "zpool export"
           first, the device appears as potentially active. It cannot be
           determined if this was a failed export, or whether the device is
           really in use from another host. To import a pool in this state,
           the -f option is required.

           -d dir
                      Searches for devices or files in dir. The -d option can
                      be specified multiple times.


           -D
                      Imports destroyed pool. The -f option is also required.


           -f
                      Forces import, even if the pool appears to be
                      potentially active.


           -o opts
                      Comma-separated list of mount options to use when
                      mounting datasets within the pool. See zfs(1M) for a
                      description of dataset properties and mount options.


           -R root
                      Imports pool(s) with an alternate root. See the
                      "Alternate Root Pools" section.



       zpool import [-d dir] [-D] [-f] [-a]
           Imports all pools found in the search directories. Identical to the
           previous command, except that all pools with a sufficient number of
           devices available are imported. Destroyed pools, pools that were
           previously destroyed with the "-zpool destroy" command, will not be
           imported unless the -D option is specified.

           -d dir
                     Searches for devices or files in dir. The -d option can
                     be specified multiple times.


           -D
                     Imports destroyed pools only. The -f option is also
                     required.


           -f
                     Forces import, even if the pool appears to be potentially
                     active.



       zpool upgrade
           Displays all pools formatted using a different ZFS on-disk version.
           Older versions can continue to be used, but some features may not
           be available. These pools can be upgraded using "zpool upgrade -a".
           Pools that are formatted with a more recent version are also
           displayed, although these pools will be inaccessible on the system.


       zpool upgrade -v
           Displays ZFS versions supported by the current software. The
           current ZFS versions and all previous supportedversions are
           displayed, along with an explanation of the features provided with
           each version.


       zpool upgrade [-a | pool]
           Upgrades the given pool to the latest on-disk version. Once this is
           done, the pool will no longer be accessible on systems running
           older versions of the software.

           -a
                 Upgrades all pools.



       zpool history [pool] ...
           Displays the command history of the specified pools (or all pools
           if no pool is specified).


EXAMPLES
       Example 1 Creating a RAID-Z Storage Pool

       The following command creates a pool with a single raidz root vdev that
       consists of six disks.


         # zpool create tank raidz c0t0d0 c0t1d0 c0t2d0 c0t3d0 c0t4d0 c0t5d0



       Example 2 Creating a Mirrored Storage Pool

       The following command creates a pool with two mirrors, where each
       mirror contains two disks.


         # zpool create tank mirror c0t0d0 c0t1d0 mirror c0t2d0 c0t3d0



       Example 3 Creating a ZFS Storage Pool by Using Slices

       The following command creates an unmirrored pool using two disk slices.


         # zpool create tank /dev/dsk/c0t0d0s1 c0t1d0s4



       Example 4 Creating a ZFS Storage Pool by Using Files

       The following command creates an unmirrored pool using files. While not
       recommended, a pool based on files can be useful for experimental
       purposes.


         # zpool create tank /path/to/file/a /path/to/file/b



       Example 5 Adding a Mirror to a ZFS Storage Pool

       The following command adds two mirrored disks to the pool "tank",
       assuming the pool is already made up of two-way mirrors. The additional
       space is immediately available to any datasets within the pool.


         # zpool add tank mirror c1t0d0 c1t1d0



       Example 6 Listing Available ZFS Storage Pools

       The following command lists all available pools on the system. In this
       case, the pool zion is faulted due to a missing device.


       The results from this command are similar to the following:


         # zpool list
             NAME              SIZE    USED   AVAIL    CAP  HEALTH     ALTROOT
             pool             67.5G   2.92M   67.5G     0%  ONLINE     -
             tank             67.5G   2.92M   67.5G     0%  ONLINE     -
             zion                 -       -       -     0%  FAULTED    -



       Example 7 Destroying a ZFS Storage Pool

       The following command destroys the pool "tank" and any datasets
       contained within.


         # zpool destroy -f tank



       Example 8 Exporting a ZFS Storage Pool

       The following command exports the devices in pool tank so that they can
       be relocated or later imported.


         # zpool export tank



       Example 9 Importing a ZFS Storage Pool

       The following command displays available pools, and then imports the
       pool "tank" for use on the system.


       The results from this command are similar to the following:


         # zpool import
          pool: tank
            id: 15451357997522795478
         state: ONLINE
         action: The pool can be imported using its name or numeric identifier.
         config:

                tank        ONLINE
                  mirror    ONLINE
                    c1t2d0  ONLINE
                    c1t3d0  ONLINE

         # zpool import tank



       Example 10 Upgrading All ZFS Storage Pools to the Current Version

       The following command upgrades all ZFS Storage pools to the current
       version of the software.


         # zpool upgrade -a
         This system is currently running ZFS version 2.



       Example 11 Managing Hot Spares

       The following command creates a new pool with an available hot spare:


         # zpool create tank mirror c0t0d0 c0t1d0 spare c0t2d0



       If one of the disks were to fail, the pool would be reduced to the
       degraded state. The failed device can be replaced using the following
       command:


         # zpool replace tank c0t0d0 c0t3d0



       Once the data has been resilvered, the spare is automatically removed
       and is made available should another device fails.  The hot spare can
       be permanently removed from the pool using the following command:


         # zpool remove tank c0t2d0



EXIT STATUS
       The following exit values are returned:

       0
            Successful completion.


       1
            An error occurred.


       2
            Invalid command line options were specified.


ATTRIBUTES
       See attributes(5) for descriptions of the following attributes:





SEE ALSO
       zfs(1M), attributes(5)



SunOS 5.11                        14 Nov 2006                        zpool(1M)