NAME¶

SYNOPSIS¶

OPTIONS:
-b, --background
--cachepolicy Policy
--cachepool CachePoolLogicalVolume{Name|Path}
--cachesettings Key=Value
-c, --chunksize ChunkSize[b|B|s|S|k|K|m|M|g|G]
--corelog
--discards {ignore|nopassdown|passdown}
-i, --interval Seconds
--merge
--mirrorlog {disk|core|mirrored}
-m, --mirrors Number
-n, --name Name
--noudevsync
--originname NewExternalOriginVolumeName
--poolmetadata PoolMetadataLogicalVolume{Name|Path}
--poolmetadatasize PoolMetadataSize[b|B|s|S|k|K|m|M|g|G]
--poolmetadataspare {y|n}
-r, --readahead {ReadAheadSectors|auto|none}
-R, --regionsize MirrorLogRegionSize
--repair
--replace PhysicalVolume
--splitcache
--splitmirrors Number
--splitsnapshot
--stripes Number
-I, --stripesize StripeSize
--type striped
--type snapshot | --snapshot | -s
--type mirror
--type raid*
--type thin | --thin | -T
--type cache | --cache | -H
--type thin-pool
--type cache-pool
--thinpool ThinPoolLogicalVolume{Name|Path}
--trackchanges
--uncache
-Z, --zero {y|n}

Common options:
-A, --alloc AllocationPolicy
-f, --force
--commandprofile ProfileName
-h, -?, --help
-v, --verbose
-y, --yes
--version

DESCRIPTION¶

To display the current LV type, run the command:

lvs -o name,segtype VG/LV

To change the LV type, run the command:

lvconvert --type NewType VG/LV

COMMANDS¶

OPTIONS¶

-b, --background
If the operation requires polling, this option causes the command to return before the operation is complete, and polling is done in the background.

--cachepolicy Policy
Specifies the cache policy for a cache LV. Also see lvmcache(7).

--cachepool CachePoolLogicalVolume{Name|Path}
Specifies the cache pool to use when converting an LV to a cache LV. If CachePoolLogicalVolume is not yet a cache pool, the command will attempt to convert it into a cache pool prior to the cache LV conversion. Also see lvmcache(7).

--cachesettings Key=Value
Specifies tunable values for a cache LV. (The default values should usually be adequate.) The special string value default switches settings back to their default kernel values and removes them from the list of settings stored in LVM metadata. Also see lvmcache(7).

-c, --chunksize ChunkSize[b|B|s|S|k|K|m|M|g|G]
Sets the chunk size for a snapshot, cache pool or thin pool. The default unit is in kilobytes.

For snapshots, the value must be a power of 2 between 4KiB and 512KiB and the default value is 4.

For a cache pool the value must be between 32KiB and 1GiB and the default value is 64.

For a thin pool the value must be between 64KiB and 1GiB and the default value starts with 64 and scales up to fit the pool metadata size within 128MiB, if the pool metadata size is not specified. The value must be a multiple of 64KiB. (Early kernel support until thin target version 1.4 required the value to be a power of 2. Discards were not supported for non-power of 2 values until thin target version 1.5.)

--corelog
Specifies or changes the log type for a mirror LV. It is an alias for --mirrorlog core. (This option does not apply to the raid1 LV type.)

--discards {ignore|nopassdown|passdown}
Specifies if discards will be processed by the thin layer in the kernel and passed down to the Physical Volume. This applies only to thin pools. The default is passdown. Also see lvmthin(7).

-H, --cache
Alias for --type cache. See COMMANDS description for
lvconvert --type cache.

-i, --interval Seconds
Report progress as a percentage at regular intervals.

--merge
Merges a snapshot that was split from an origin LV using --splitsnapshot, back into the origin LV.

Merges a raid1 image that was split from a raid1 LV using --splitsnapshot and --trackchanges, back into the original raid1 LV.

To check if the kernel supports the snapshot merge feature, look for "snapshot-merge" in the output of dmsetup targets.

When merging a snapshot, if both the origin and snapshot LVs are not open, the merge will start immediately. Otherwise, the merge will start the first time either the origin or snapshot LV are activated and both are closed. Merging a snapshot into an origin that cannot be closed, for example a root filesystem, is deferred until the next time the origin volume is activated. When merging starts, the resulting LV will have the origin's name, minor number and UUID. While the merge is in progress, reads or writes to the origin appear as being directed to the snapshot being merged. When the merge finishes, the merged snapshot is removed. Multiple snapshots may be specified on the command line or a @tag may be used to specify multiple snapshots be merged to their respective origin.

--mirrorlog {disk|core|mirrored}
Specifies or changes the log type for a mirror LV. The default is disk, which is persistent and requires a small amount of storage space, usually on a separate device from the data being mirrored. Core may be useful for short-lived mirrors. It means the mirror is regenerated by copying the data from the first device again every time the device is activated - e.g. possibly after every reboot. Using mirrored will create a persistent log that is itself mirrored. (This option does not apply to the raid1 LV type.)

-m, --mirrors Number
Specifies the number mirror images in addition to the original LV image, e.g. --mirrors 1 means two copies of the data, the original and one mirror image.

The current maximum is 9 providing 10 raid1 images.

This option is required when converting an LV to a raid1 or mirror LV.

This option can be used alone to change the number of mirror images in an existing raid1 or mirror LV.

The special case --mirrors 0 has been used historically to indicate a linear LV with no mirror images.

-n, --name Name
Specifies the name to use when the command is creating a new LV, e.g. --splitmirrors.

--noudevsync
Disables udev synchronisation. The process will not wait for notification from udev. It will continue irrespective of any possible udev processing in the background. You should only use this if udev is not running or has rules that ignore the devices LVM creates.

--originname NewExternalOriginVolumeName
Specifies the name to use for the external origin LV when converting an LV to a thin LV. The LV being converted becomes a read-only external origin with this name.
Without this option, the default name of "lvol<n>" will be generated where <n> is the LVM internal number of the LV.

--poolmetadata PoolMetadataLogicalVolume{Name|Path}
Specifies the LV to use for thin pool metadata when converting an LV to a thin pool LV.
Specifies the LV to use for cache pool metadata when converting an LV to a cache pool LV.
The size should be between 2MiB and 16GiB.
(This option can also be used when a thin pool or cache pool are created as an auxiliary operation within a different command.) Also see lvmthin(7), and lvmcache(7).

--poolmetadatasize PoolMetadataSize[b|B|s|S|k|K|m|M|g|G]
Specifies the size of a cache pool metadata LV or a thin pool metadata LV. This is used if a command creates a pool metadata LV automatically as part of the operation. This option is not used when an existing LV is specified as the pool metadata LV, i.e. --poolmetadata. The default unit is megabytes. Also see lvmthin(7), and lvmcache(7).

--poolmetadataspare {y|n}
Specifies if a spare pool metadata LV should be created. A spare pool metadata LV will be used for pool repair. Only one spare pool metadata LV is maintained within a VG, with the size of the largest existing pool metadata LV. The default is yes.

-r, --readahead {ReadAheadSectors|auto|none}
Specifies the read ahead sector count of a thin pool metadata LV. The default value is auto which allows the kernel to choose a suitable value automatically. None is equivalent to specifying zero.

-R, --regionsize MirrorLogRegionSize
A mirror LV is divided into regions of this size (in MB), and the mirror log uses this granularity to track which regions are in sync. (This option does not apply to the raid1 LV type.)

--repair
Replaces failed PVs in a raid1 or mirror LV with other PVs available in the VG. By default, the original number of mirror images will be restored if possible. Specify -y on the command line to skip the prompts. Use -f if you do not want any replacement. You may use --use-policies to use the device replacement policy specified in lvm.conf(5), see activation/mirror_log_fault_policy or activation/mirror_device_fault_policy.

When used with a thin pool LV, this option automates the use of the thin_repair(8) tool on the thin pool. This repairs a very limitted number of problems. Only inactive thin pools can be repaired. There is no validation of metadata between kernel and LVM. This requires further manual work. After successfull repair the old unmodified metadata are still available in "<pool>_meta<n>" LV. Also see lvmthin(7).

--replace PhysicalVolume
Remove the specified device PhysicalVolume and replace it with one that is available in the VG, or from a specific list of PVs specified on the command line following the LV name. This option may be repeated multiple times depending on the RaidLV type.

-s, --snapshot
Alias for --type snapshot. See COMMANDS description for
lvconvert --type snapshot.

--split
Separates SplitableLogicalVolume. This option tries to detect the necessary split operation from its arguments. Avoid using this option and use one of the following instead: --splitcache, --splitmirrors, --splitsnapshot.

--splitcache
Separates a cache pool from a cache LV, and keeps the unused cache pool LV. Before the separation, the cache is flushed. See similar option --uncache. Also see lvmcache(7).

--splitmirrors Number
Splits the specified number of images from a raid1 or mirror LV and uses them to create a new LV.

If --trackchanges is also specified, changes to the raid1 LV are tracked while the split LV remains detached. lvconvert --merge can be used to recombine the split images with the original raid1 LV.

A name can be specified for the new LV with --name (a name is required without --trackchanges).

--splitsnapshot
Separates a COW snapshot from its origin LV. The LV that is split off contains the chunks that differ from the origin LV along with metadata describing them. This LV can be wiped and then destroyed with lvremove. See corresponding operation lvconvert --type snapshot.

--stripes Number
Specifies the number of stripes in a striped LV. This is the number of physical volumes (devices) that a striped LV is spread across. Data that appears sequential in the LV is spread across multiple devices in units of the stripe size (see --stripesize). This does not apply to existing allocated space, only newly allocated space can be striped.

-I, --stripesize StripeSize
Specifies the stripe size in kilobytes for a striped LV. The stripe size is the number of kilobytes written to each stripe, i.e. to one device, before writing to the next stripe/device. StripeSize must be a power of 2 and cannot exceed the VG physical extent (PE) size.

--type SegmentType
Converts an LV from one segment type to another. See COMMANDS section for a description of converting between each type.

--thinpool ThinPoolLogicalVolume{Name|Path}
Specifies the thin pool to use when converting an LV to a thin LV. If ThinPoolLogicalVolume is not yet a thin pool, the command will attempt to convert it to a thin pool prior to the thin LV conversion. Also see lvmthin(7).

--trackchanges
Can be used with --splitmirrors on a raid1 LV. This causes changes to the original raid1 LV to be tracked while the split images remain detached. This allows the read-only detached image(s) to be merged efficiently back into the raid1 LV later. Only the regions with changed data are resynchronized during merge. (This option only applies to the raid1 LV type.)

-T, --thin
Alias for --type thin. See COMMANDS description for
lvconvert --type thin.

--uncache
Separates a cache pool from a cache LV, and removes the unused cache pool LV. Before the separation, the cache is flushed. See similar option --splitcache. Also see lvmcache(7).

-Z, --zero {y|n}
For snapshots, this controls zeroing of the first 4KiB of data in the snapshot. If the LV is read-only, the snapshot will not be zeroed.

For thin pools, this controls zeroing of provisioned blocks. Provisioning of large zeroed chunks negatively impacts performance. Also see lvmthin(7).

Examples¶

Convert a linear LV to a two-way RAID1 LV:
lvconvert --type raid1 --mirrors 1 vg/lvol1

Convert a mirror LV to use an in-memory log:
lvconvert --mirrorlog core vg/lvol1

Convert a mirror LV to use a disk log:
lvconvert --mirrorlog disk vg/lvol1

Convert a mirror or raid1 LV to a linear LV:
lvconvert --type linear vg/lvol1

Convert a mirror LV to a raid1 LV with the same number of images:
lvconvert --type raid1 vg/lvol1

Convert a linear LV to a two-way mirror LV, allocating new extents from specific PV ranges:
lvconvert --mirrors 1 vg/lvol1 /dev/sda:0-15 /dev/sdb:0-15

Convert a mirror LV to a linear LV, freeing physical extents from a specific PV:
lvconvert --type linear vg/lvol1 /dev/sda

Split one image from a mirror or raid1 LV, making it a new LV:
lvconvert --splitmirrors 1 --name lv_split vg/lvol1

Split one image from a raid1 LV, and track changes made to the raid1 LV while the split image remains detached:
lvconvert --splitmirrors 1 --trackchanges vg/lvol1

Merge an image (that was previously created with --splitmirrors and --trackchanges) back into the original raid1 LV:
lvconvert --merge vg/lvol1_rimage_1

Replace PV /dev/sdb1 with PV /dev/sdf1 in a raid1/4/5/6/10 LV:
lvconvert --replace /dev/sdb1 vg/lvol1 /dev/sdf1

Replace 3 PVs /dev/sd[b-d]1 with PVs /dev/sd[f-h]1 in a raid1 LV:
lvconvert --replace /dev/sdb1 --replace /dev/sdc1 --replace /dev/sdd1

Replace the maximum of 2 PVs /dev/sd[bc]1 with PVs /dev/sd[gh]1 in a raid6 LV:
lvconvert --replace /dev/sdb1 --replace /dev/sdc1 vg/lvol1 /dev/sd[gh]1

Convert an LV into a thin LV in the specified thin pool. The existing LV is used as an external read-only origin for the new thin LV.
lvconvert --type thin --thinpool vg/tpool1 vg/lvol1

Convert an LV into a thin LV in the specified thin pool. The existing LV is used as an external read-only origin for the new thin LV, and is renamed "external":
lvconvert --type thin --thinpool vg/tpool1

Convert an LV to a cache pool LV using another specified LV for cache pool metadata:
lvconvert --type cache-pool --poolmetadata vg/poolmeta1 vg/lvol1

Convert an LV to a cache LV using the specified cache pool and chunk size:
lvconvert --type cache --cachepool vg/cpool1 -c 128 vg/lvol1

Detach and keep the cache pool from a cache LV:
lvconvert --splitcache vg/lvol1

Detach and remove the cache pool from a cache LV:
lvconvert --uncache vg/lvol1

SEE ALSO¶