| Main index | Section 8 | Options |
All datasets within a storage pool share the same space. See zfs(8) for information on managing datasets.
| disk | A block device, typically located under /dev. 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 to the device or the geom(4) provider name. 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 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 |
(or
raidz1 raidz2 raidz3).
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 single-, double- , or triple parity, meaning that the raidz group can sustain one, two, or three failures, respectively, without losing any data. The raidz1 vdev type specifies a single-parity raidz group; the raidz2 vdev type specifies a double-parity raidz group; and the raidz3 vdev type specifies a triple-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 P device(s) 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 to help increase performance. |
| spare | A special pseudo-vdev which keeps track of available hot spares for a pool. For more information, see the "Sx Hot Spares" section. |
| log | A separate-intent log device. If more than one log device is specified, then writes are load-balanced between devices. Log devices can be mirrored. However, raidz vdev types are not supported for the intent log. For more information, see the "Sx Intent Log" section. |
| dedup | A device dedicated solely for allocating dedup data. The redundancy of this device should match the redundancy of the other normal devices in the pool. If more than one dedup device is specified, then allocations are load-balanced between devices. |
| special | |
|
A device dedicated solely for allocating various kinds of internal metadata,
and optionally small file data.
The redundancy of this device should match the redundancy of the other normal
devices in the pool.
If more than one special device is specified, then allocations are
load-balanced between devices.
For more information on special allocations, see the Special Allocation Class section. | |
| cache | A device used to cache storage pool data. A cache device cannot be configured as a mirror or raidz group. For more information, see the "Sx Cache Devices" 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 da0 da1 mirror da2 da3
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 corrupted metadata, or one or more faulted devices, and insufficient replicas to continue functioning.
The health of the top-level vdev, such as mirror or raidz device, is potentially impacted by the state of its associated vdevs, or component devices. A top-level vdev or component device is in one of the following states:
| DEGRADED | |
|
One or more top-level
vdevs
is in the degraded state because one or more
component devices are offline. Sufficient replicas exist to continue
functioning.
One or more component devices is in the degraded or faulted state, but sufficient replicas exist to continue functioning. The underlying conditions are as follows:
| |
| FAULTED |
One or more top-level
vdevs
is in the faulted state because one or more
component devices are offline. Insufficient replicas exist to continue
functioning.
One or more component devices is in the faulted state, and insufficient replicas exist to continue functioning. The underlying conditions are as follows:
|
| OFFLINE | The device was explicitly taken offline by the "Cm" command. |
| ONLINE | The device is online and functioning. |
| REMOVED | The device was physically removed while the system was running. Device removal detection is hardware-dependent and may not be supported on all platforms. |
| UNAVAIL | The device could not be opened. If a pool is imported when a device was unavailable, then the device will be identified by a unique identifier instead of its path since the path was never correct in the first place. |
If a device is removed and later reattached to the system, ZFS attempts to put the device online automatically. Device attach detection is hardware-dependent and might not be supported on all platforms.
# zpool create pool mirror da0 da1 spare da2 da3
Spares can be shared across multiple pools, and can be added with the "Cm" command and removed with the "Cm" 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.
If a pool has a shared spare that is currently being used, the pool can not be exported since other pools may use this shared spare, which may lead to potential data corruption.
Shared spares add some risk. If the pools are imported on different hosts, and both pools suffer a device failure at the same time, both could attempt to use the spare at the same time. This may not be detected, resulting in data corruption.
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.
Spares cannot replace log devices.
This feature requires a userland helper. FreeBSD provides zfsd(8) for this purpose. It must be manually enabled by adding zfsd_enable="YES" to /etc/rc.conf.
# zpool create pool da0 da1 log da2
Multiple log devices can also be specified, and they can be mirrored. See the EXAMPLES section for an example of mirroring multiple log devices.
Log devices can be added, replaced, attached, detached, imported and exported as part of the larger pool. Mirrored devices can be removed by specifying the top-level mirror vdev.
To create a pool with cache devices, specify a "cache" vdev with any number of devices. For example:
# zpool create pool da0 da1 cache da2 da3
Cache devices cannot be mirrored or part of a raidz configuration. If a read error is encountered on a cache device, that read I/O is reissued to the original storage pool device, which might be part of a mirrored or raidz configuration.
The content of the cache devices is considered volatile, as is the case with other system caches.
A pool checkpoint can be thought of as a pool-wide snapshot and should be used with care as it contains every part of the pool's state, from properties to vdev configuration. Thus, while a pool has a checkpoint certain operations are not allowed. Specifically, vdev removal/attach/detach, mirror splitting, and changing the pool's guid. Adding a new vdev is supported but in the case of a rewind it will have to be added again. Finally, users of this feature should keep in mind that scrubs in a pool that has a checkpoint do not repair checkpointed data.
To create a checkpoint for a pool:
# zpool checkpoint pool
To later rewind to its checkpointed state, you need to first export it and then rewind it during import:
# zpool export pool # zpool import --rewind-to-checkpoint pool
To discard the checkpoint from a pool:
# zpool checkpoint -d pool
Dataset reservations (controlled by the reservation or refreservation zfs properties) may be unenforceable while a checkpoint exists, because the checkpoint is allowed to consume the dataset's reservation. Finally, data that is part of the checkpoint but has been freed in the current state of the pool won't be scanned during a scrub.
A pool must always have at least one general (non-specified) vdev before other devices can be assigned to the special class. If the special class becomes full, then allocations intended for it will spill back into the normal class.
Dedup data can be excluded from the special class by setting the vfs.zfs.ddt_data_is_special sysctl to false (0).
Inclusion of small file blocks in the special class is opt-in. Each dataset can control the size of small file blocks allowed in the special class by setting the special_small_blocks dataset property. It defaults to zero so you must opt-in by setting it to a non-zero value. See zfs(1M) for more info on setting this property.
| allocated | Amount of storage space used within the pool. |
| capacity | Percentage of pool space used. This property can also be referred to by its shortened column name, "cap". |
| dedupratio | |
| The deduplication ratio specified for a pool, expressed as a multiplier. For example, a dedupratio value of 1.76 indicates that 1.76 units of data were stored but only 1 unit of disk space was actually consumed. See zfs(8) for a description of the deduplication feature. | |
| expandsize | |
| Amount of uninitialized space within the pool or device that can be used to increase the total capacity of the pool. Uninitialized space consists of any space on an EFI labeled vdev which has not been brought online (i.e. zpool online -e). This space occurs when a LUN is dynamically expanded. | |
| fragmentation | |
| The amount of fragmentation in the pool. | |
| free | Number of blocks within the pool that are not allocated. |
| freeing | After a file system or snapshot is destroyed, the space it was using is returned to the pool asynchronously. freeing is the amount of space remaining to be reclaimed. Over time freeing will decrease while free increases. |
| guid | A unique identifier for the pool. |
| load_guid | A unique identifier for the pool. Unlike the guid property, this identifier is generated every time we load the pool (e.g. does not persist across imports/exports) and never changes while the pool is loaded (even if a reguid operation takes place). |
| health | The current health of the pool. Health can be " ONLINE", " DEGRADED", " FAULTED", " OFFLINE", " REMOVED", or " UNAVAIL". |
| size | Total size of the storage pool. |
| unsupported@feature_guid | |
| Information about unsupported features that are enabled on the pool. See zpool-features(7) for details. | |
The space usage properties report 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(8) command takes into account, but the zpool(8) 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.
The following property can be set at creation time and import time:
| altroot | |
| Alternate root directory. If set, this directory is prepended to any mount points within the pool. This can be used when examining an unknown pool where the mount points cannot be trusted, or in an alternate boot environment, where the typical paths are not valid. altroot is not a persistent property. It is valid only while the system is up. Setting altroot defaults to using cachefile=none, though this may be overridden using an explicit setting. | |
The following property can only be set at import time:
| readonly= on | off | |
If set to
on,
pool will be imported in read-only mode with the following restrictions:
This property can also be referred to by its shortened column name, rdonly. | |
The following properties can be set at creation time and import time, and later changed with the zpool set command:
| autoexpand= on | off | |
| Controls automatic pool expansion when the underlying LUN is grown. If set to " on", the pool will be resized according to the size of the expanded device. If the device is part of a mirror or raidz then all devices within that mirror/raidz group must be expanded before the new space is made available to the pool. The default behavior is "off". This property can also be referred to by its shortened column name, expand. | |
| autoreplace= on | off | |
| Controls automatic device replacement. If set to " off", device replacement must be initiated by the administrator by using the "Cm" command. If set to " on", any new device, found in the same physical location as a device that previously belonged to the pool, is automatically formatted and replaced. The default behavior is " off". This property can also be referred to by its shortened column name, "replace". | |
| bootfs=pool/dataset | |
| Identifies the default bootable dataset for the root pool. This property is expected to be set mainly by the installation and upgrade programs. | |
| cachefile=path | none | |
| Controls the location of where the pool configuration is cached. Discovering all pools on system startup requires a cached copy of the configuration data that is stored on the root file system. All pools in this cache are automatically imported when the system boots. Some environments, such as install and clustering, need to cache this information in a different location so that pools are not automatically imported. Setting this property caches the pool configuration in a different location that can later be imported with "Cm". Setting it to the special value " none" creates a temporary pool that is never cached, and the special value '' (empty string) uses the default location. | |
| comment=text | |
| A text string consisting of printable ASCII characters that will be stored such that it is available even if the pool becomes faulted. An administrator can provide additional information about a pool using this property. | |
| dedupditto=number | |
| Threshold for the number of block ditto copies. If the reference count for a deduplicated block increases above this number, a new ditto copy of this block is automatically stored. Default setting is 0 which causes no ditto copies to be created for deduplicated blocks. The miniumum legal nonzero setting is 100. | |
| delegation= on | off | |
| Controls whether a non-privileged user is granted access based on the dataset permissions defined on the dataset. See zfs(8) for more information on ZFS delegated administration. | |
| failmode= wait | continue | panic | |
| Controls the system behavior in the event of catastrophic pool failure. This condition is typically a result of a loss of connectivity to the underlying storage device(s) or a failure of all devices within the pool. The behavior of such an event is determined as follows: | |
| wait | Blocks all I/O access until the device connectivity is recovered and the errors are cleared. This is the default behavior. |
| continue | |
| Returns EIO to any new write I/O requests but allows reads to any of the remaining healthy devices. Any write requests that have yet to be committed to disk would be blocked. | |
| panic | Prints out a message to the console and generates a system crash dump. |
| feature@feature_name= enabled | |
| The value of this property is the current state of feature_name. The only valid value when setting this property is enabled which moves feature_name to the enabled state. See zpool-features(7) for details on feature states. | |
| listsnapshots= on | off | |
|
Controls whether information about snapshots associated with this pool is
output when
"zfs"
is run without the
| |
| multihost= on | off | |
|
Controls whether a pool activity check should be performed during
zpool.
When a pool is determined to be active it cannot be imported, even with the
Multihost provides protection on import only. It does not protect against an individual device being used in multiple pools, regardless of the type of vdev. See the discussion under zpool create. When this property is on, periodic writes to storage occur to show the pool is in use. See vfs.zfs.multihost_interval sysctl. In order to enable this property each host must set a unique hostid. The default value is off. | |
| version=version | |
| The current on-disk version of the pool. This can be increased, but never decreased. The preferred method of updating pools is with the "Cm" command, though this property can be used when a specific version is needed for backwards compatibility. Once feature flags is enabled on a pool this property will no longer have a value. | |
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
add
[
Adds the specified virtual devices to the given pool. The
vdev
specification is described in the
"Sx Virtual Devices"
section. The behavior of the
| |
| | |
| Forces use of vdev, even if they appear in use or specify a conflicting replication level. Not all devices can be overridden in this manner. | |
| | |
| Display vdev, GUIDs instead of the normal device names. These GUIDs can be used in place of device names for the zpool detach/offline/remove/replace commands. | |
| | |
| Display real paths for vdevs resolving all symbolic links. This can be used to look up the current block device name regardless of the /dev/disk/ path used to open it. | |
| | |
| 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. | |
| | |
|
Display real paths for
vdevs
instead of only the last component of the path.
This can be used in conjunction with the
| |
| zpool
attach
[ 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. | |
| | |
| Forces use of new_device, even if its appears to be in use. Not all devices can be overridden in this manner. | |
| zpool
checkpoint
[ | |
| | |
| Discards an existing checkpoint from pool. | |
| zpool
clear
[ 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. If multihost is enabled, and the pool has been suspended, this will not resume I/O. While the pool was suspended, it may have been imported on another host, and resuming I/O could result in pool damage. | |
| | |
| Initiates recovery mode for an unopenable pool. Attempts to discard the last few transactions in the pool to return it to an openable state. Not all damaged pools can be recovered by using this option. If successful, the data from the discarded transactions is irretrievably lost. | |
| | |
|
Used in combination with the
| |
| zpool
create
[ 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", "spare" and "log" are reserved, as are names beginning with the pattern "c[0-9]". The vdev specification is described in the "Sx Virtual Devices" section. The command attempts to verify that each device specified is accessible and not currently in use by another subsystem. However this check is not robust enough to detect simultaneous attempts to use a new device in different pools, even if multihost is enabled. The administrator must ensure that simultaneous invocations of any combination of zpool replace, zpool create, zpool add, or zpool labelclear, do not refer to the same device. Using the same device in two pools will result in pool corruption.
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
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
Unless the
By default all supported features are enabled on the new pool unless the
| |
| | |
| 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. | |
| | |
| 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. | |
| | |
|
Do not enable any features on the new pool.
Individual features can be enabled by setting their corresponding properties
to
enabled
with the
| |
| | |
|
Equivalent to
" | |
| | |
| Sets the mount point for the root dataset. The default mount point is " /pool" or " altroot /pool" if altroot is specified. The mount point must be an absolute path, " legacy", or " none". For more information on dataset mount points, see zfs(8). | |
| | |
| Sets the in-core pool name to tempname while the on-disk name will be the name specified as the pool name pool. This will set the default cachefile property to none. This is intended to handle name space collisions when creating pools for other systems, such as virtual machines or physical machines whose pools live on network block devices. | |
| zpool
destroy
[ Destroys the given pool, freeing up any devices for other use. This command tries to unmount any active datasets before destroying the pool. | |
| | |
| Forces any active datasets contained within the pool to be unmounted. | |
| zpool
detach
pool device
Detaches device from a mirror. The operation is refused if there are no other valid replicas of the data. | |
| zpool
export
[ 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. A pool can not be exported if it has a shared spare that is currently being used. 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. | |
| | |
|
Forcefully unmount all datasets, using the
"unmount"
command.
This command will forcefully export the pool even if it has a shared spare that is currently being used. This may lead to potential data corruption. | |
| zpool
get
[ Retrieves the given list of properties (or all properties if " all" is used) for the specified storage pool(s). These properties are displayed with the following fields:
See the "Sx Properties" section for more information on the available pool properties. | |||||||||
| | |||||||||
| Scripted mode. Do not display headers, and separate fields by a single tab instead of arbitrary space. | |||||||||
| | |||||||||
| Display numbers in parsable (exact) values. | |||||||||
| | |||||||||
| A comma-separated list of columns to display. name, property, value, source is the default value. | |||||||||
| zpool
history
[ Displays the command history of the specified pools or all pools if no pool is specified. | |||||||||
| | |||||||||
| Displays internally logged ZFS events in addition to user initiated events. | |||||||||
| | |||||||||
| Displays log records in long format, which in addition to standard format includes, the user name, the hostname, and the zone in which the operation was performed. | |||||||||
| zpool
import
[
Lists pools available to import. If the
The numeric identifier is unique, and can be used instead of the pool name when multiple exported pools of the same name are available. | |
| | |
| Reads configuration from the given cachefile that was created with the " cachefile" pool property. This cachefile is used instead of searching for devices. | |
| | |
|
Searches for devices or files in
dir.
The
| |
| | |
| Lists destroyed pools only. | |
| zpool
import
[
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
"Cm"
command, will not be imported unless the
| |
| | |
| Comma-separated list of mount options to use when mounting datasets within the pool. See zfs(8) for a description of dataset properties and mount options. | |
| | |
| Sets the specified property on the imported pool. See the "Sx Properties" section for more information on the available pool properties. | |
| | |
| Reads configuration from the given cachefile that was created with the " cachefile" pool property. This cachefile is used instead of searching for devices. | |
| | |
|
Searches for devices or files in
dir.
The
| |
| | |
|
Imports destroyed pools only. The
| |
| | |
| Forces import, even if the pool appears to be potentially active. | |
| | |
| Allows a pool to import when there is a missing log device. Recent transactions can be lost because the log device will be discarded. | |
| | |
| Import the pool without mounting any file systems. | |
| | |
| Sets the " cachefile" property to " none" and the " altroot" property to "root" | |
| | |
| Recovery mode for a non-importable pool. Attempt to return the pool to an importable state by discarding the last few transactions. Not all damaged pools can be recovered by using this option. If successful, the data from the discarded transactions is irretrievably lost. This option is ignored if the pool is importable or already imported. | |
| | |
|
Used with the
| |
| | |
| Searches for and imports all pools found. | |
| zpool
import
[ 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
"Cm"
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
| |
| | |
| Comma-separated list of mount options to use when mounting datasets within the pool. See zfs(8) for a description of dataset properties and mount options. | |
| | |
| Sets the specified property on the imported pool. See the "Sx Properties" section for more information on the available pool properties. | |
| | |
| Reads configuration from the given cachefile that was created with the " cachefile" pool property. This cachefile is used instead of searching for devices. | |
| | |
|
Searches for devices or files in
dir.
The
| |
| | |
|
Imports destroyed pools only. The
| |
| | |
| Forces import, even if the pool appears to be potentially active. | |
| | |
| Allows a pool to import when there is a missing log device. Recent transactions can be lost because the log device will be discarded. | |
| | |
| Import the pool without mounting any file systems. | |
| | |
|
Equivalent to
" | |
| | |
| Used with newpool. Specifies that newpool is temporary. Temporary pool names last until export. Ensures that the original pool name will be used in all label updates and therefore is retained upon export. Will also set cachefile property to none when not explicitly specified. | |
| | |
| Recovery mode for a non-importable pool. Attempt to return the pool to an importable state by discarding the last few transactions. Not all damaged pools can be recovered by using this option. If successful, the data from the discarded transactions is irretrievably lost. This option is ignored if the pool is importable or already imported. | |
| | |
|
Used with the
| |
| | |
| Rewinds pool to the checkpointed state. Once the pool is imported with this flag there is no way to undo the rewind. All changes and data that were written after the checkpoint are lost! The only exception is when the readonly mounting option is enabled. In this case, the checkpointed state of the pool is opened and an administrator can see how the pool would look like if they were to fully rewind. | |
| zpool
initialize
[ | |
| | |
| Cancel initializing on the specified devices, or all eligible devices if none are specified. If one or more target devices are invalid or are not currently being initialized, the command will fail and no cancellation will occur on any device. | |
| | |
| Suspend initializing on the specified devices, or all eligible devices if none are specified. If one or more target devices are invalid or are not currently being initialized, the command will fail and no suspension will occur on any device. Initializing can then be resumed by running zpool with no flags on the relevant target devices. | |
| zpool
iostat
[ 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. | |
| | |
|
Print a timestamp.
Use modifier d for standard date format. See date(1). Use modifier u for unixtime (equals " date +%s"). | |
| | |
| Display vdev GUIDs instead of the normal device names. These GUIDs can be used in place of device names for the zpool detach/offline/remove/replace commands. | |
| | |
| Display real paths for vdevs resolving all symbolic links. This can be used to look up the current block device name regardless of the /dev/disk/ path used to open it. | |
| | |
|
Display full paths for vdevs instead of only the last component of
the path.
This can be used in conjunction with the
| |
| | |
| Verbose statistics. Reports usage statistics for individual vdevs within the pool, in addition to the pool-wide statistics. | |
| zpool
labelclear
[ Removes ZFS label information from the specified device. The device must not be part of an active pool configuration. | |
| | |
| Treat exported or foreign devices as inactive. | |
| zpool
list
[ Lists the given pools along with a health status and space usage. If no pools are specified, all pools in the system are listed. When given an interval, the output is printed every interval seconds until Ctrl-C is pressed. If count is specified, the command exits after count reports are printed. | |
| | |
|
Print a timestamp.
Use modifier d for standard date format. See date(1). Use modifier u for unixtime (equals " date +%s"). | |
| | |
| Display vdev GUIDs instead of the normal device names. These GUIDs can be used in place of device names for the zpool detach/offline/remove/replace commands. | |
| | |
| Scripted mode. Do not display headers, and separate fields by a single tab instead of arbitrary space. | |
| | |
| Display real paths for vdevs resolving all symbolic links. This can be used to look up the current block device name regardless of the /dev/disk/ path used to open it. | |
| | |
| Display numbers in parsable (exact) values. | |
| | |
|
Display full paths for vdevs instead of only the last component of
the path.
This can be used in conjunction with the
| |
| | |
| Verbose statistics. Reports usage statistics for individual vdevs within the pool, in addition to the pool-wide statistics. | |
| | |
| Comma-separated list of properties to display. See the "Sx Properties" section for a list of valid properties. The default list is name, size, allocated, free, checkpoint, expandsize, fragmentation, capacity, dedupratio, health, altroot. | |
| | |
|
Print a timestamp.
Use modifier d for standard date format. See date(1). Use modifier u for unixtime (equals " date +%s"). | |
| zpool
offline
[ Takes the specified physical device offline. While the device is offline, no attempt is made to read or write to the device. | |
| | |
| Temporary. Upon reboot, the specified physical device reverts to its previous state. | |
| zpool
online
[ Brings the specified physical device online. This command is not applicable to spares or cache devices. | |
| | |
| Expand the device to use all available space. If the device is part of a mirror or raidz then all devices must be expanded before the new space will become available to the pool. | |
| zpool
reguid
pool
Generates a new unique identifier for the pool. You must ensure that all devices in this pool are online and healthy before performing this action. | |
| zpool
remove
[ Removes the specified device from the pool. This command currently only supports removing hot spares, cache, log devices and mirrored top-level vdevs (mirror of leaf devices); but not raidz. Removing a top-level vdev reduces the total amount of space in the storage pool. The specified device will be evacuated by copying all allocated space from it to the other devices in the pool. In this case, the zpool command initiates the removal and returns, while the evacuation continues in the background. The removal progress can be monitored with zpool This feature must be enabled to be used, see zpool-features(7) A mirrored top-level device (log or data) can be removed by specifying the top-level mirror for the same. Non-log devices or data devices that are part of a mirrored configuration can be removed using the "Cm" command. | |
| | |
| Do not actually perform the removal ("no-op"). Instead, print the estimated amount of memory that will be used by the mapping table after the removal completes. This is nonzero only for top-level vdevs. | |
| | |
|
Used in conjunction with the
| |
| zpool
remove
Stops and cancels an in-progress removal of a top-level vdev. | |
| zpool
reopen
pool
Reopen all the vdevs associated with the pool. | |
| zpool
replace
[ 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. new_device is required if the pool is not redundant. 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 path as the old device, even though it is actually a different disk. ZFS recognizes this. | |
| | |
| Forces use of new_device, even if its appears to be in use. Not all devices can be overridden in this manner. | |
| zpool
scrub
[ Begins a scrub or resumes a paused 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 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 paused, the zpool resumes it. If a resilver is in progress, ZFS does not allow a scrub to be started until the resilver completes. | |
| | |
| Stop scrubbing. | |
| | |
| Pause scrubbing. Scrub pause state and progress are periodically synced to disk. If the system is restarted or pool is exported during a paused scrub, even after import, scrub will remain paused until it is resumed. Once resumed the scrub will pick up from the place where it was last checkpointed to disk. To resume a paused scrub issue zpool again. | |
| zpool
set
property=value pool
Sets the given property on the specified pool. See the "Sx Properties" section for more information on what properties can be set and acceptable values. | |
| zpool
split
[ Splits off one disk from each mirrored top-level vdev in a pool and creates a new pool from the split-off disks. The original pool must be made up of one or more mirrors and must not be in the process of resilvering. The split subcommand chooses the last device in each mirror vdev unless overridden by a device specification on the command line.
When using a
device
argument,
split
includes the specified device(s) in a new pool and, should any devices remain
unspecified, assigns the last device in each mirror
vdev
to that pool, as it does normally. If you are uncertain about the outcome of a
split
command, use the
| |
| | |
| Automatically import the newly created pool after splitting, using the specified altroot parameter for the new pool's alternate root. See the altroot description in the "Sx Properties" section, above. | |
| | |
| Display vdev GUIDs instead of the normal device names. These GUIDs can be used in place of device names for the zpool detach/offline/remove/replace commands. | |
| | |
| Display real paths for vdevs resolving all symbolic links. This can be used to look up the current block device name regardless of the /dev/disk/ path used to open it. | |
| | |
| Displays the configuration that would be created without actually splitting the pool. The actual pool split could still fail due to insufficient privileges or device status. | |
| | |
|
Comma-separated list of mount options to use when mounting datasets within the
pool. See
zfs(8)
for a description of dataset properties and mount options. Valid only in
conjunction with the
| |
| | |
| Sets the specified property on the new pool. See the "Sx Properties" section, above, for more information on the available pool properties. | |
| | |
|
Display full paths for vdevs instead of only the last component of
the path.
This can be used in conjunction with the
| |
| zpool
status
[ 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. For more information on pool and device health, see the "Sx Device Failure and Recovery" section. When given an interval, the output is printed every interval seconds until Ctrl-C is pressed. If count is specified, the command exits after count reports are printed. 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. | |
| | |
| Display a histogram of deduplication statistics, showing the allocated (physically present on disk) and referenced (logically referenced in the pool) block counts and sizes by reference count. | |
| | |
| Display vdev GUIDs instead of the normal device names. These GUIDs can be used in place of device names for the zpool detach/offline/remove/replace commands. | |
| | |
| Display real paths for vdevs resolving all symbolic links. This can be used to look up the current block device name regardless of the /dev/disk/ path used to open it. | |
| | |
|
Display full paths for vdevs instead of only the last component of
the path.
This can be used in conjunction with the
| |
| | |
|
Print a timestamp.
Use modifier d for standard date format. See date(1). Use modifier u for unixtime (equals " date +%s"). | |
| | |
| Displays verbose data error information, printing out a complete list of all data errors since the last complete pool scrub. | |
| | |
| Only display status for pools that are exhibiting errors or are otherwise unavailable. Warnings about pools not using the latest on-disk format, having non-native block size or disabled features will not be included. | |
| zpool sync [pool ]... Forces all in-core dirty data to be written to the primary pool storage and not the ZIL. It will also update administrative information including quota reporting. Without arguments, zpool will sync all pools on the system. Otherwise, it will only sync the specified pool. | |
| zpool
upgrade
[ Displays pools which do not have all supported features enabled and pools formatted using a legacy ZFS version number. These pools can continue to be used, but some features may not be available. Use Cm to enable all features on all pools. | |
| | |
| Displays legacy ZFS versions supported by the current software. See zpool-features(7) for a description of feature flags features supported by the current software. | |
| zpool
upgrade
[ Enables all supported features on the given pool. Once this is done, the pool will no longer be accessible on systems that do not support feature flags. See zpool-features(7) for details on compatibility with systems that support feature flags, but do not support all features enabled on the pool. | |
| | |
| Enables all supported features on all pools. | |
| | |
|
Upgrade to the specified legacy version. If the
| |
| 0 | Successful completion. |
| 1 | An error occurred. |
| 2 | Invalid command line options were specified. |
| ZPOOL_VDEV_NAME_GUID | Cause zpool subcommands to output vdev guids by default. This behavior is identical to the zpool command line option. |
| ZPOOL_VDEV_NAME_FOLLOW_LINKS | |
| Cause zpool subcommands to follow links for vdev names by default. This behavior is identical to the zpool command line option. | |
| ZPOOL_VDEV_NAME_PATH | Cause zpool subcommands to output full vdev path names by default. This behavior is identical to the zpool command line option. |
| 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 da0 da1 da2 da3 da4 da5 | |
| 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 da0 da1 mirror da2 da3 | |
| Example 3 Creating a ZFS Storage Pool by Using Partitions | |
|
The following command creates an unmirrored pool using two GPT partitions. # zpool create tank da0p3 da1p3 | |
| 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 da2 da3 | |
| Example 6 Listing Available ZFS Storage Pools | |
|
The following command lists all available pools on the system. # zpool list NAME SIZE ALLOC FREE FRAG EXPANDSZ CAP DEDUP HEALTH ALTROOT pool 2.70T 473G 2.24T 33% - 17% 1.00x ONLINE - test 1.98G 89.5K 1.98G 48% - 0% 1.00x ONLINE - | |
| Example 7 Listing All Properties for a Pool | |
|
The following command lists all the properties for a pool. # zpool get all pool pool size 2.70T - pool capacity 17% - pool altroot - default pool health ONLINE - pool guid 2501120270416322443 default pool version 28 default pool bootfs pool/root local pool delegation on default pool autoreplace off default pool cachefile - default pool failmode wait default pool listsnapshots off default pool autoexpand off default pool dedupditto 0 default pool dedupratio 1.00x - pool free 2.24T - pool allocated 473G - pool readonly off - | |
| Example 8 Destroying a ZFS Storage Pool | |
|
The following command destroys the pool " tank" and any datasets contained within. # zpool destroy -f tank | |
| Example 9 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 10 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 | |
| Example 11
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 pool version 28. | |
| Example 12 Managing Hot Spares | |
|
The following command creates a new pool with an available hot spare: # zpool create tank mirror da0 da1 spare da2 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 da0 da2 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 da2 | |
| Example 13
Creating a
ZFS
Pool with Mirrored Separate Intent Logs
The following command creates a ZFS storage pool consisting of two, two-way mirrors and mirrored log devices: # zpool create pool mirror da0 da1 mirror da2 da3 log mirror da4 da5 | |
| Example 14 Adding Cache Devices to a ZFS Pool | |
|
The following command adds two disks for use as cache devices to a ZFS storage pool: # zpool add pool cache da2 da3 Once added, the cache devices gradually fill with content from main memory. Depending on the size of your cache devices, it could take over an hour for them to fill. Capacity and reads can be monitored using the iostat subcommand as follows: # zpool iostat -v pool 5 | |
| Example 15
Displaying expanded space on a device
The following command dipslays the detailed information for the data pool. This pool is comprised of a single raidz vdev where one of its devices increased its capacity by 10GB. In this example, the pool will not be able to utilized this extra capacity until all the devices under the raidz vdev have been expanded.
# zpool list -v data
NAME SIZE ALLOC FREE FRAG EXPANDSZ CAP DEDUP HEALTH ALTROOT
data 23.9G 14.6G 9.30G 48% - 61% 1.00x ONLINE -
raidz1 23.9G 14.6G 9.30G 48% -
ada0 - - - - -
ada1 - - - - 10G
ada2 - - - - -
| |
| Example 16
Removing a Mirrored top-level (Log or Data) Device
The following commands remove the mirrored log device mirror-2 and mirrored top-level data device mirror-1. Given this configuration: pool: tank state: ONLINE scrub: none requested config: The command to remove the mirrored log mirror-2 is: # zpool remove tank mirror-2 The command to remove the mirrored data mirror-1 is: # zpool remove tank mirror-1 | |
| Example 17
Recovering a Faulted
ZFS
Pool
If a pool is faulted but recoverable, a message indicating this state is
provided by
"Cm"
if the pool was cached (see the
Recover a cached pool with the "Cm" command: # zpool clear -F data Pool data returned to its state as of Tue Sep 08 13:23:35 2009. Discarded approximately 29 seconds of transactions. If the pool configuration was not cached, use "Cm" with the recovery mode flag: # zpool import -F data Pool data returned to its state as of Tue Sep 08 13:23:35 2009. Discarded approximately 29 seconds of transactions. | |
The mdoc(7) implementation of this manual page was initially written by Martin Matuska <mm@FreeBSD.org>.
| ZPOOL (8) | February 25, 2020 |
| Main index | Section 8 | Options |
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| “ | If at first you don't succeed, you must be a programmer. | ” |