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NAME | SYNOPSIS | DESCRIPTION | USAGE | OPTIONS | VARIABLES | ENVIRONMENT VARIABLES | ADVANCED USAGE | NOTES | EXAMPLES | SEE ALSO | COLOPHON |
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LVCONVERT(8) System Manager's Manual LVCONVERT(8)
lvconvert — Change logical volume layout
lvconvert option_args position_args
[ option_args ]
[ position_args ]
--alloc contiguous|cling|cling_by_tags|normal|anywhere|inherit
-b|--background
-H|--cache
--cachedevice PV
--cachemetadataformat auto|1|2
--cachemode writethrough|writeback|passthrough
--cachepolicy String
--cachepool LV
--cachesettings String
--cachesize Size[m|UNIT]
--cachevol LV
-c|--chunksize Size[k|UNIT]
--commandprofile String
--compression y|n
--config String
-d|--debug
--deduplication y|n
--devices PV
--devicesfile String
--discards passdown|nopassdown|ignore
--driverloaded y|n
--errorwhenfull y|n
-f|--force
-h|--help
-i|--interval Number
--journal String
--lockopt String
--longhelp
--merge
--mergemirrors
--mergesnapshot
--mergethin
--metadataprofile String
--mirrorlog core|disk
-m|--mirrors [+|-]Number
-n|--name String
--nohints
--nolocking
--noudevsync
--originname LV
--poolmetadata LV
--poolmetadatasize Size[m|UNIT]
--poolmetadataspare y|n
--profile String
-q|--quiet
--raidintegrity y|n
--raidintegrityblocksize Number
--raidintegritymode String
-r|--readahead auto|none|Number
-R|--regionsize Size[m|UNIT]
--repair
--replace PV
-s|--snapshot
--splitcache
--splitmirrors Number
--splitsnapshot
--startpoll
--stripes Number
-I|--stripesize Size[k|UNIT]
--swapmetadata
-t|--test
-T|--thin
--thinpool LV
--trackchanges
--type linear|striped|snapshot|raid|mirror|thin|thin-pool|vdo|
vdo-pool|cache|cache-pool|writecache
--uncache
--usepolicies
--vdopool LV
-v|--verbose
--version
-V|--virtualsize Size[m|UNIT]
-y|--yes
-Z|--zero y|n
lvconvert changes the LV type and includes utilities for LV data
maintenance. The LV type controls data layout and redundancy. The
LV type is also called the segment type or segtype.
To display the current LV type, run the command:
lvs -o name,segtype LV
In some cases, an LV is a single device mapper (dm) layer above
physical devices. In other cases, hidden LVs (dm devices) are
layered between the visible LV and physical devices. LVs in the
middle layers are called sub LVs. A command run on a visible LV
sometimes operates on a sub LV rather than the specified LV. In
other cases, a sub LV must be specified directly on the command
line.
Sub LVs can be displayed with the command:
lvs -a
The linear type is equivalent to the striped type when one stripe
exists. In that case, the types can sometimes be used inter‐
changeably.
In most cases, the mirror type is deprecated and the raid1 type
should be used. They are both implementations of mirroring.
Striped raid types are raid0/raid0_meta, raid5 (an alias for
raid5_ls), raid6 (an alias for raid6_zr) and raid10 (an alias for
raid10_near).
As opposed to mirroring, raid5 and raid6 stripe data and calculate
parity blocks. The parity blocks can be used for data block recov‐
ery in case devices fail. A maximum number of one device in a
raid5 LV may fail, and two in case of raid6. Striped raid types
typically rotate the parity and data blocks for performance rea‐
sons, thus avoiding contention on a single device. Specific
arrangements of parity and data blocks (layouts) can be used to
optimize I/O performance, or to convert between raid levels. See
lvmraid(7) for more information.
Layouts of raid5 rotating parity blocks can be: left-asymmetric
(raid5_la), left-symmetric (raid5_ls with alias raid5), right-
asymmetric (raid5_ra), right-symmetric (raid5_rs) and raid5_n,
which doesn't rotate parity blocks. Layouts of raid6 are: zero-
restart (raid6_zr with alias raid6), next-restart (raid6_nr), and
next-continue (raid6_nc).
Layouts including _n allow for conversion between raid levels
(raid5_n to raid6 or raid5_n to striped/raid0/raid0_meta). Addi‐
tionally, special raid6 layouts for raid level conversions between
raid5 and raid6 are: raid6_ls_6, raid6_rs_6, raid6_la_6 and
raid6_ra_6. Those correspond to their raid5 counterparts (e.g.
raid5_rs can be directly converted to raid6_rs_6 and vice-versa).
raid10 (an alias for raid10_near) is currently limited to one data
copy and even number of sub LVs. This is a mirror group layout,
thus a single sub LV may fail per mirror group without data loss.
Striped raid types support converting the layout, their stripesize
and their number of stripes.
The striped raid types combined with raid1 allow for conversion
from linear → striped/raid0/raid0_meta and vice-versa by e.g. lin‐
ear ↔ raid1 ↔ raid5_n (then adding stripes) ↔
striped/raid0/raid0_meta.
Convert LV to linear.
lvconvert --type linear LV
[ COMMON_OPTIONS ]
[ PV ... ]
—
Convert LV to striped.
lvconvert --type striped LV
[ -I|--stripesize Size[k|UNIT] ]
[ -R|--regionsize Size[m|UNIT] ]
[ -i|--interval Number ]
[ --stripes Number ]
[ COMMON_OPTIONS ]
[ PV ... ]
—
Convert LV to type mirror (also see type raid1),
lvconvert --type mirror LV
[ -m|--mirrors [+|-]Number ]
[ -I|--stripesize Size[k|UNIT] ]
[ -R|--regionsize Size[m|UNIT] ]
[ -i|--interval Number ]
[ --stripes Number ]
[ --mirrorlog core|disk ]
[ COMMON_OPTIONS ]
[ PV ... ]
—
Convert LV to raid or change raid layout
(a specific raid level must be used, e.g. raid1).
lvconvert --type raid LV
[ -m|--mirrors [+|-]Number ]
[ -I|--stripesize Size[k|UNIT] ]
[ -R|--regionsize Size[m|UNIT] ]
[ -i|--interval Number ]
[ --stripes Number ]
[ COMMON_OPTIONS ]
[ PV ... ]
—
Convert LV to raid1 or mirror, or change number of mirror images.
lvconvert -m|--mirrors [+|-]Number LV
[ -R|--regionsize Size[m|UNIT] ]
[ -i|--interval Number ]
[ --mirrorlog core|disk ]
[ COMMON_OPTIONS ]
[ PV ... ]
—
Convert raid LV to change number of stripe images.
lvconvert --stripes Number LV1
[ -i|--interval Number ]
[ -R|--regionsize Size[m|UNIT] ]
[ -I|--stripesize Size[k|UNIT] ]
[ COMMON_OPTIONS ]
[ PV ... ]
LV1 types: raid
—
Convert raid LV to change the stripe size.
lvconvert -I|--stripesize Size[k|UNIT] LV1
[ -i|--interval Number ]
[ -R|--regionsize Size[m|UNIT] ]
[ COMMON_OPTIONS ]
LV1 types: raid
—
Split images from a raid1 or mirror LV and use them to create a
new LV.
lvconvert --splitmirrors Number -n|--name LV_new LV1
[ COMMON_OPTIONS ]
[ PV ... ]
LV1 types: cache mirror raid1
—
Split images from a raid1 LV and track changes to origin for later
merge.
lvconvert --splitmirrors Number --trackchanges LV1
[ COMMON_OPTIONS ]
[ PV ... ]
LV1 types: cache raid1
—
Merge LV images that were split from a raid1 LV.
lvconvert --mergemirrors VG|LV1|Tag ...
[ COMMON_OPTIONS ]
LV1 types: linear raid
—
Convert LV to a thin LV, using the original LV as an external ori‐
gin.
lvconvert --type thin --thinpool LV LV1
[ -T|--thin ]
[ -r|--readahead auto|none|Number ]
[ -c|--chunksize Size[k|UNIT] ]
[ -Z|--zero y|n ]
[ --originname LV_new ]
[ --poolmetadata LV ]
[ --poolmetadatasize Size[m|UNIT] ]
[ --poolmetadataspare y|n ]
[ --metadataprofile String ]
[ COMMON_OPTIONS ]
LV1 types: linear striped thin cache raid error zero
—
Attach a cache pool to an LV, converts the LV to type cache.
lvconvert --type cache --cachepool LV LV1
[ -H|--cache ]
[ -Z|--zero y|n ]
[ -r|--readahead auto|none|Number ]
[ -c|--chunksize Size[k|UNIT] ]
[ --cachemetadataformat auto|1|2 ]
[ --cachemode writethrough|writeback|passthrough ]
[ --cachepolicy String ]
[ --cachesettings String ]
[ --poolmetadata LV ]
[ --poolmetadatasize Size[m|UNIT] ]
[ --poolmetadataspare y|n ]
[ --metadataprofile String ]
[ COMMON_OPTIONS ]
LV1 types: linear striped thinpool vdo vdopool vdopooldata
raid
—
Attach a writecache to an LV, converts the LV to type writecache.
lvconvert --type writecache --cachevol LV LV1
[ --cachesettings String ]
[ COMMON_OPTIONS ]
LV1 types: linear striped thinpool raid
—
Attach a cache to an LV, converts the LV to type cache.
lvconvert --type cache --cachevol LV LV1
[ -H|--cache ]
[ -Z|--zero y|n ]
[ -c|--chunksize Size[k|UNIT] ]
[ --cachemetadataformat auto|1|2 ]
[ --cachemode writethrough|writeback|passthrough ]
[ --cachepolicy String ]
[ --cachesettings String ]
[ --poolmetadatasize Size[m|UNIT] ]
[ COMMON_OPTIONS ]
LV1 types: linear striped thinpool raid
—
Add a writecache to an LV, using a specified cache device.
lvconvert --type writecache --cachedevice PV LV1
[ --cachesize Size[m|UNIT] ]
[ --cachesettings String ]
[ COMMON_OPTIONS ]
LV1 types: linear striped thinpool raid
—
Add a cache to an LV, using a specified cache device.
lvconvert --type cache --cachedevice PV LV1
[ -c|--chunksize Size[k|UNIT] ]
[ --cachesize Size[m|UNIT] ]
[ --cachesettings String ]
[ COMMON_OPTIONS ]
LV1 types: linear striped thinpool raid
—
Convert LV to type thin-pool.
lvconvert --type thin-pool LV1
[ -I|--stripesize Size[k|UNIT] ]
[ -r|--readahead auto|none|Number ]
[ -c|--chunksize Size[k|UNIT] ]
[ -Z|--zero y|n ]
[ --stripes Number ]
[ --discards passdown|nopassdown|ignore ]
[ --errorwhenfull y|n ]
[ --poolmetadata LV ]
[ --poolmetadatasize Size[m|UNIT] ]
[ --poolmetadataspare y|n ]
[ --metadataprofile String ]
[ COMMON_OPTIONS ]
[ PV ... ]
LV1 types: linear striped cache raid error zero writecache
—
Convert LV to type cache-pool.
lvconvert --type cache-pool LV1
[ -Z|--zero y|n ]
[ -r|--readahead auto|none|Number ]
[ -c|--chunksize Size[k|UNIT] ]
[ --cachemetadataformat auto|1|2 ]
[ --cachemode writethrough|writeback|passthrough ]
[ --cachepolicy String ]
[ --cachesettings String ]
[ --poolmetadata LV ]
[ --poolmetadatasize Size[m|UNIT] ]
[ --poolmetadataspare y|n ]
[ --metadataprofile String ]
[ COMMON_OPTIONS ]
[ PV ... ]
LV1 types: linear striped raid
—
Convert LV to type vdopool.
lvconvert --type vdo-pool LV1
[ -n|--name LV_new ]
[ -V|--virtualsize Size[m|UNIT] ]
[ -r|--readahead auto|none|Number ]
[ -Z|--zero y|n ]
[ --metadataprofile String ]
[ --compression y|n ]
[ --deduplication y|n ]
[ COMMON_OPTIONS ]
LV1 types: linear striped cache raid
—
Detach a cache from an LV.
lvconvert --splitcache LV1
[ --cachesettings String ]
[ COMMON_OPTIONS ]
LV1 types: thinpool cache cachepool vdopool writecache
—
Merge thin LV into its origin LV.
lvconvert --mergethin LV1 ...
[ COMMON_OPTIONS ]
LV1 types: thin
—
Merge COW snapshot LV into its origin.
lvconvert --mergesnapshot LV1 ...
[ -i|--interval Number ]
[ COMMON_OPTIONS ]
LV1 types: snapshot
—
Combine a former COW snapshot (second arg) with a former
origin LV (first arg) to reverse a splitsnapshot command.
lvconvert --type snapshot LV LV1
[ -s|--snapshot ]
[ -c|--chunksize Size[k|UNIT] ]
[ -Z|--zero y|n ]
[ COMMON_OPTIONS ]
LV1 types: linear striped
—
Replace failed PVs in a raid or mirror LV.
Repair a thin pool.
Repair a cache pool.
lvconvert --repair LV1
[ -i|--interval Number ]
[ --usepolicies ]
[ --poolmetadataspare y|n ]
[ COMMON_OPTIONS ]
[ PV ... ]
LV1 types: thinpool cache cachepool mirror raid
—
Replace specific PV(s) in a raid LV with another PV.
lvconvert --replace PV LV1
[ COMMON_OPTIONS ]
[ PV ... ]
LV1 types: raid
—
Poll LV to continue conversion.
lvconvert --startpoll LV1
[ COMMON_OPTIONS ]
LV1 types: mirror raid
—
Add or remove data integrity checksums to raid images.
lvconvert --raidintegrity y|n LV1
[ --raidintegritymode String ]
[ --raidintegrityblocksize Number ]
[ COMMON_OPTIONS ]
[ PV ... ]
LV1 types: raid
—
Common options for command:
[ -b|--background ]
[ -f|--force ]
[ --alloc contiguous|cling|cling_by_tags|normal|anywhere|
inherit ]
[ --noudevsync ]
Common options for lvm:
[ -d|--debug ]
[ -h|--help ]
[ -q|--quiet ]
[ -t|--test ]
[ -v|--verbose ]
[ -y|--yes ]
[ --commandprofile String ]
[ --config String ]
[ --devices PV ]
[ --devicesfile String ]
[ --driverloaded y|n ]
[ --journal String ]
[ --lockopt String ]
[ --longhelp ]
[ --nohints ]
[ --nolocking ]
[ --profile String ]
[ --version ]
--alloc contiguous|cling|cling_by_tags|normal|anywhere|inherit
Determines the allocation policy when a command needs to
allocate Physical Extents (PEs) from the VG. Each VG and LV
has an allocation policy which can be changed with
vgchange/lvchange, or overridden on the command line. nor‐
mal applies common sense rules such as not placing parallel
stripes on the same PV. inherit applies the VG policy to
an LV. contiguous requires new PEs be placed adjacent to
existing PEs. cling places new PEs on the same PV as ex‐
isting PEs in the same stripe of the LV. If there are suf‐
ficient PEs for an allocation, but normal does not use
them, anywhere will use them even if it reduces perfor‐
mance, e.g. by placing two stripes on the same PV. Option‐
al positional PV args on the command line can also be used
to limit which PVs the command will use for allocation.
See lvm(8) for more information about allocation.
-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.
-H|--cache
Specifies the command is handling a cache LV or cache pool.
See --type cache and --type cache-pool. See lvmcache(7)
for more information about LVM caching.
--cachedevice PV
The name of a device to use for a cache.
--cachemetadataformat auto|1|2
Specifies the cache metadata format used by cache target.
--cachemode writethrough|writeback|passthrough
Specifies when writes to a cache LV should be considered
complete. writeback considers a write complete as soon as
it is stored in the cache pool. writethough considers a
write complete only when it has been stored in both the
cache pool and on the origin LV. While writethrough may be
slower for writes, it is more resilient if something should
happen to a device associated with the cache pool LV. With
passthrough, all reads are served from the origin LV (all
reads miss the cache) and all writes are forwarded to the
origin LV; additionally, write hits cause cache block in‐
validates. See lvmcache(7) for more information.
--cachepolicy String
Specifies the cache policy for a cache LV. See lvmcache(7)
for more information.
--cachepool LV
The name of a cache pool.
--cachesettings String
Specifies tunable values for a cache LV in "Key = Value"
form. Repeat this option to specify multiple values. (The
default values should usually be adequate.) The special
string value default switches settings back to their de‐
fault kernel values and removes them from the list of set‐
tings stored in LVM metadata. See lvmcache(7) for more in‐
formation.
--cachesize Size[m|UNIT]
The size of cache to use.
--cachevol LV
The name of a cache volume.
-c|--chunksize Size[k|UNIT]
The size of chunks in a snapshot, cache pool or thin pool.
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. See lvmthin(7) and lvmcache(7) for
more information.
--commandprofile String
The command profile to use for command configuration. See
lvm.conf(5) for more information about profiles.
--compression y|n
Controls whether compression is enabled or disable for VDO
volume. See lvmvdo(7) for more information about VDO us‐
age.
--config String
Config settings for the command. These override lvm.conf(5)
settings. The String arg uses the same format as
lvm.conf(5), or may use section/field syntax. See
lvm.conf(5) for more information about config.
-d|--debug ...
Set debug level. Repeat from 1 to 6 times to increase the
detail of messages sent to the log file and/or syslog (if
configured).
--deduplication y|n
Controls whether deduplication is enabled or disable for
VDO volume. See lvmvdo(7) for more information about VDO
usage.
--devices PV
Devices that the command can use. This option can be re‐
peated or accepts a comma separated list of devices. This
overrides the devices file.
--devicesfile String
A file listing devices that LVM should use. The file must
exist in /etc/lvm/devices/ and is managed with the
lvmdevices(8) command. This overrides the lvm.conf(5) de‐
vices/devicesfile and devices/use_devicesfile settings.
--discards passdown|nopassdown|ignore
Specifies how the device-mapper thin pool layer in the ker‐
nel should handle discards. ignore causes the thin pool to
ignore discards. nopassdown causes the thin pool to
process discards itself to allow reuse of unneeded extents
in the thin pool. passdown causes the thin pool to process
discards itself (like nopassdown) and pass the discards to
the underlying device. See lvmthin(7) for more informa‐
tion.
--driverloaded y|n
If set to no, the command will not attempt to use device-
mapper. For testing and debugging.
--errorwhenfull y|n
Specifies thin pool behavior when data space is exhausted.
When yes, device-mapper will immediately return an error
when a thin pool is full and an I/O request requires space.
When no, device-mapper will queue these I/O requests for a
period of time to allow the thin pool to be extended. Er‐
rors are returned if no space is available after the time‐
out. (Also see dm-thin-pool kernel module option
no_space_timeout.) See lvmthin(7) for more information.
-f|--force ...
Override various checks, confirmations and protections.
Use with extreme caution.
-h|--help
Display help text.
-i|--interval Number
Report progress at regular intervals.
--journal String
Record information in the systemd journal. This informa‐
tion is in addition to information enabled by the lvm.conf
log/journal setting. command: record information about the
command. output: record the default command output. de‐
bug: record full command debugging.
--lockopt String
Used to pass options for special cases to lvmlockd. See
lvmlockd(8) for more information.
--longhelp
Display long help text.
--merge
An alias for --mergethin, --mergemirrors, or --mergesnap‐
shot, depending on the type of LV.
--mergemirrors
Merge LV images that were split from a raid1 LV. See
--splitmirrors with --trackchanges.
--mergesnapshot
Merge COW snapshot LV into its origin. 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 filesys‐
tem, 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 be‐
ing directed to the snapshot being merged. When the merge
finishes, the merged snapshot is removed. Multiple snap‐
shots may be specified on the command line or a @tag may be
used to specify multiple snapshots be merged to their re‐
spective origin.
--mergethin
Merge thin LV into its origin LV. The origin thin LV takes
the content of the thin snapshot, and the thin snapshot LV
is removed. See lvmthin(7) for more information.
--metadataprofile String
The metadata profile to use for command configuration. See
lvm.conf(5) for more information about profiles.
--mirrorlog core|disk
Specifies the type of mirror log for LVs with the "mirror"
type (does not apply to the "raid1" type.) disk is a per‐
sistent log and requires a small amount of storage space,
usually on a separate device from the data being mirrored.
core is not persistent; the log is kept only in memory. In
this case, the mirror must be synchronized (by copying LV
data from the first device to others) each time the LV is
activated, e.g. after reboot. mirrored is a persistent log
that is itself mirrored, but should be avoided. Instead,
use the raid1 type for log redundancy.
-m|--mirrors [+|-]Number
Specifies the number of mirror images in addition to the
original LV image, e.g. --mirrors 1 means there are two im‐
ages of the data, the original and one mirror image. Op‐
tional positional PV args on the command line can specify
the devices the images should be placed on. There are two
mirroring implementations: "raid1" and "mirror". These are
the names of the corresponding LV types, or "segment
types". Use the --type option to specify which to use
(raid1 is default, and mirror is legacy) Use lvm.conf(5)
global/mirror_segtype_default and global/raid10_segtype_de‐
fault to configure the default types. The plus prefix +
can be used, in which case the number is added to the cur‐
rent number of images, or the minus prefix - can be used,
in which case the number is subtracted from the current
number of images. See lvmraid(7) for more information.
-n|--name String
Specifies the name of a new LV. When unspecified, a de‐
fault name of "lvol#" is generated, where # is a number
generated by LVM.
--nohints
Do not use the hints file to locate devices for PVs. A com‐
mand may read more devices to find PVs when hints are not
used. The command will still perform standard hint file in‐
validation where appropriate.
--nolocking
Disable locking.
--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. Only use
this if udev is not running or has rules that ignore the
devices LVM creates.
--originname LV
Specifies the name to use for the external origin LV when
converting an LV to a thin LV. The LV being converted be‐
comes a read-only external origin with this name.
--poolmetadata LV
The name of a an LV to use for storing pool metadata.
--poolmetadatasize Size[m|UNIT]
Specifies the size of the new pool metadata LV.
--poolmetadataspare y|n
Enable or disable the automatic creation and management of
a spare pool metadata LV in the VG. A spare metadata LV is
reserved space that can be used when repairing a pool.
--profile String
An alias for --commandprofile or --metadataprofile, depend‐
ing on the command.
-q|--quiet ...
Suppress output and log messages. Overrides --debug and
--verbose. Repeat once to also suppress any prompts with
answer 'no'.
--raidintegrity y|n
Enable or disable data integrity checksums for raid images.
--raidintegrityblocksize Number
The block size to use for dm-integrity on raid images. The
integrity block size should usually match the device logi‐
cal block size, or the file system block size. It may be
less than the file system block size, but not less than the
device logical block size. Possible values: 512, 1024,
2048, 4096.
--raidintegritymode String
Use a journal (default) or bitmap for keeping integrity
checksums consistent in case of a crash. The bitmap areas
are recalculated after a crash, so corruption in those ar‐
eas would not be detected. A journal does not have this
problem. The journal mode doubles writes to storage, but
can improve performance for scattered writes packed into a
single journal write. bitmap mode can in theory achieve
full write throughput of the device, but would not benefit
from the potential scattered write optimization.
-r|--readahead auto|none|Number
Sets read ahead sector count of an LV. auto is the default
which allows the kernel to choose a suitable value automat‐
ically. none is equivalent to zero.
-R|--regionsize Size[m|UNIT]
Size of each raid or mirror synchronization region.
lvm.conf(5) activation/raid_region_size can be used to con‐
figure a default.
--repair
Replace failed PVs in a raid or mirror LV, or run a repair
utility on a thin pool. See lvmraid(7) and lvmthin(7) for
more information.
--replace PV
Replace a specific PV in a raid LV with another PV. The
new PV to use can be optionally specified after the LV.
Multiple PVs can be replaced by repeating this option. See
lvmraid(7) for more information.
-s|--snapshot
Combine a former COW snapshot LV with a former origin LV to
reverse a previous --splitsnapshot command.
--splitcache
Separates a cache pool from a cache LV, and keeps the un‐
used cache pool LV. Before the separation, the cache is
flushed. Also see --uncache.
--splitmirrors Number
Splits the specified number of images from a raid1 or mir‐
ror 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. If --name is speci‐
fied, then the images are permanently split from the origi‐
nal LV and changes are not tracked.
--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.
--startpoll
Start polling an LV to continue processing a conversion.
--stripes Number
Specifies the number of stripes in a striped LV. This is
the number of PVs (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 Size[k|UNIT]
The amount of data that is written to one device before
moving to the next in a striped LV.
--swapmetadata
Extracts the metadata LV from a pool and replaces it with
another specified LV. The extracted LV is preserved and
given the name of the LV that replaced it. Use for repair
only. When the metadata LV is swapped out of the pool, it
can be activated directly and used with thin provisioning
tools: cache_dump(8), cache_repair(8), cache_restore(8),
thin_dump(8), thin_repair(8), thin_restore(8).
-t|--test
Run in test mode. Commands will not update metadata. This
is implemented by disabling all metadata writing but never‐
theless returning success to the calling function. This may
lead to unusual error messages in multi-stage operations if
a tool relies on reading back metadata it believes has
changed but hasn't.
-T|--thin
Specifies the command is handling a thin LV or thin pool.
See --type thin, --type thin-pool, and --virtualsize. See
lvmthin(7) for more information about LVM thin provision‐
ing.
--thinpool LV
The name of a thin pool LV.
--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 is a temporary state
that allows the read-only detached image to be merged effi‐
ciently back into the raid1 LV later. Only the regions
with changed data are resynchronized during merge. While a
raid1 LV is tracking changes, operations on it are limited
to merging the split image (see --mergemirrors) or perma‐
nently splitting the image (see --splitmirrors with --name.
--type linear|striped|snapshot|raid|mirror|thin|thin-pool|vdo|
vdo-pool|cache|cache-pool|writecache
The LV type, also known as "segment type" or "segtype".
See usage descriptions for the specific ways to use these
types. For more information about redundancy and perfor‐
mance (raid<N>, mirror, striped, linear) see lvmraid(7).
For thin provisioning (thin, thin-pool) see lvmthin(7).
For performance caching (cache, cache-pool) see
lvmcache(7). For copy-on-write snapshots (snapshot) see
usage definitions. For VDO (vdo) see lvmvdo(7). Several
commands omit an explicit type option because the type is
inferred from other options or shortcuts (e.g. --stripes,
--mirrors, --snapshot, --virtualsize, --thin, --cache,
--vdo). Use inferred types with care because it can lead
to unexpected results.
--uncache
Separates a cache pool from a cache LV, and deletes the un‐
used cache pool LV. Before the separation, the cache is
flushed. Also see --splitcache.
--usepolicies
Perform an operation according to the policy configured in
lvm.conf(5) or a profile.
--vdopool LV
The name of a VDO pool LV. See lvmvdo(7) for more informa‐
tion about VDO usage.
-v|--verbose ...
Set verbose level. Repeat from 1 to 4 times to increase the
detail of messages sent to stdout and stderr.
--version
Display version information.
-V|--virtualsize Size[m|UNIT]
The virtual size of a new thin LV. See lvmthin(7) for more
information about LVM thin provisioning. Using virtual
size (-V) and actual size (-L) together creates a sparse
LV. lvm.conf(5) global/sparse_segtype_default determines
the default segment type used to create a sparse LV. Any‐
thing written to a sparse LV will be returned when reading
from it. Reading from other areas of the LV will return
blocks of zeros. When using a snapshot to create a sparse
LV, a hidden virtual device is created using the zero tar‐
get, and the LV has the suffix _vorigin. Snapshots are
less efficient than thin provisioning when creating large
sparse LVs (GiB).
-y|--yes
Do not prompt for confirmation interactively but always as‐
sume the answer yes. Use with extreme caution. (For auto‐
matic no, see -qq.)
-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.
VG Volume Group name. See lvm(8) for valid names.
LV Logical Volume name. See lvm(8) for valid names. An LV
positional arg generally includes the VG name and LV name,
e.g. VG/LV. LV1 indicates the LV must have a specific
type, where the accepted LV types are listed. (raid repre‐
sents raid<N> type).
PV Physical Volume name, a device path under /dev. For com‐
mands managing physical extents, a PV positional arg gener‐
ally accepts a suffix indicating a range (or multiple
ranges) of physical extents (PEs). When the first PE is
omitted, it defaults to the start of the device, and when
the last PE is omitted it defaults to end. Start and end
range (inclusive): PV[:PE-PE]... Start and length range
(counting from 0): PV[:PE+PE]...
Tag Tag name. See lvm(8) for information about tag names and
using tags in place of a VG, LV or PV.
String See the option description for information about the string
content.
Size[UNIT]
Size is an input number that accepts an optional unit. In‐
put units are always treated as base two values, regardless
of capitalization, e.g. 'k' and 'K' both refer to 1024.
The default input unit is specified by letter, followed by
|UNIT. UNIT represents other possible input units: b|B is
bytes, s|S is sectors of 512 bytes, k|K is KiB, m|M is MiB,
g|G is GiB, t|T is TiB, p|P is PiB, e|E is EiB. (This
should not be confused with the output control --units,
where capital letters mean multiple of 1000.)
See lvm(8) for information about environment variables used by
lvm. For example, LVM_VG_NAME can generally be substituted for a
required VG parameter.
Alternate command forms, advanced command usage, and listing of
all valid syntax for completeness.
Change the region size of an LV.
lvconvert -R|--regionsize Size[m|UNIT] LV1
[ COMMON_OPTIONS ]
LV1 types: raid
—
Change the type of mirror log used by a mirror LV.
lvconvert --mirrorlog core|disk LV1
[ COMMON_OPTIONS ]
[ PV ... ]
LV1 types: mirror
—
Convert LV to a thin LV, using the original LV as an external ori‐
gin.
lvconvert -T|--thin --thinpool LV LV1
[ --type thin ] (implied)
[ -r|--readahead auto|none|Number ]
[ -c|--chunksize Size[k|UNIT] ]
[ -Z|--zero y|n ]
[ --originname LV_new ]
[ --poolmetadata LV ]
[ --poolmetadatasize Size[m|UNIT] ]
[ --poolmetadataspare y|n ]
[ --metadataprofile String ]
[ COMMON_OPTIONS ]
LV1 types: linear striped thin cache raid error zero
—
Attach a cache pool to an LV.
lvconvert -H|--cache --cachepool LV LV1
[ --type cache ] (implied)
[ -Z|--zero y|n ]
[ -r|--readahead auto|none|Number ]
[ -c|--chunksize Size[k|UNIT] ]
[ --cachemetadataformat auto|1|2 ]
[ --cachemode writethrough|writeback|passthrough ]
[ --cachepolicy String ]
[ --cachesettings String ]
[ --poolmetadata LV ]
[ --poolmetadatasize Size[m|UNIT] ]
[ --poolmetadataspare y|n ]
[ --metadataprofile String ]
[ COMMON_OPTIONS ]
LV1 types: linear striped thinpool vdo vdopool vdopooldata
raid
—
Attach a cache to an LV, converts the LV to type cache.
lvconvert -H|--cache --cachevol LV LV1
[ -Z|--zero y|n ]
[ -c|--chunksize Size[k|UNIT] ]
[ --cachemetadataformat auto|1|2 ]
[ --cachemode writethrough|writeback|passthrough ]
[ --cachepolicy String ]
[ --cachesettings String ]
[ --poolmetadatasize Size[m|UNIT] ]
[ COMMON_OPTIONS ]
LV1 types: linear striped thinpool raid
—
Convert LV to type vdopool.
lvconvert --vdopool LV
[ --type vdo-pool ] (implied)
[ -r|--readahead auto|none|Number ]
[ -Z|--zero y|n ]
[ -n|--name LV_new ]
[ -V|--virtualsize Size[m|UNIT] ]
[ --metadataprofile String ]
[ --compression y|n ]
[ --deduplication y|n ]
[ COMMON_OPTIONS ]
—
Detach and delete a cache from an LV.
lvconvert --uncache LV1
[ --cachesettings String ]
[ COMMON_OPTIONS ]
LV1 types: thinpool cache vdopool writecache
—
Swap metadata LV in a thin pool or cache pool (for repair only).
lvconvert --swapmetadata --poolmetadata LV LV1
[ -c|--chunksize Size[k|UNIT] ]
[ COMMON_OPTIONS ]
LV1 types: thinpool cachepool
—
Merge LV that was split from a mirror (variant, use --mergemir‐
rors).
Merge thin LV into its origin LV (variant, use --mergethin).
Merge COW snapshot LV into its origin (variant, use --mergesnap‐
shot).
lvconvert --merge VG|LV1|Tag ...
[ -i|--interval Number ]
[ COMMON_OPTIONS ]
LV1 types: linear striped snapshot thin raid
—
Separate a COW snapshot from its origin LV.
lvconvert --splitsnapshot LV1
[ COMMON_OPTIONS ]
LV1 types: snapshot
—
Combine a former COW snapshot (second arg) with a former
origin LV (first arg) to reverse a splitsnapshot command.
lvconvert -s|--snapshot LV LV1
[ --type snapshot ] (implied)
[ -c|--chunksize Size[k|UNIT] ]
[ -Z|--zero y|n ]
[ COMMON_OPTIONS ]
LV1 types: linear striped
—
Poll LV to continue conversion (also see --startpoll)
or waits till conversion/mirror syncing is finished
lvconvert LV1
[ COMMON_OPTIONS ]
LV1 types: mirror raid
—
This previous command syntax would perform two different opera‐
tions:
lvconvert --thinpool LV1 --poolmetadata LV2
If LV1 was not a thin pool, the command would convert LV1 to a
thin pool, optionally using a specified LV for metadata. But, if
LV1 was already a thin pool, the command would swap the current
metadata LV with LV2 (for repair purposes.)
In the same way, this previous command syntax would perform two
different operations:
lvconvert --cachepool LV1 --poolmetadata LV2
If LV1 was not a cache pool, the command would convert LV1 to a
cache pool, optionally using a specified LV for metadata. But, if
LV1 was already a cache pool, the command would swap the current
metadata LV with LV2 (for repair purposes.)
Convert a linear LV to a two-way mirror LV.
lvconvert --type mirror --mirrors 1 vg/lvol1
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 --mergemirrors 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 vg/lvol1 /dev/sd[fgh]1
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 a thick LV into a thin-pool data volume and continue using
this LV through thinLV and for the conversion set the pool metada‐
ta size to 1GiB.
lvconvert --type thin --poolmetadatasize 1G vg/lvol1
Convert an LV into a thin-pool with VDO deduplication and compres‐
sion for storing its data.
lvconvert --type thin-pool --pooldatavdo y vg/lvol1
Convert an LV into a thin LV in the specified thin pool. The ex‐
isting 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 ex‐
isting LV is used as an external read-only origin for the new thin
LV, and is renamed "external".
lvconvert --type thin --thinpool vg/tpool1 --originname external
vg/lvol1
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
lvm(8), lvm.conf(5), lvmconfig(8), lvmdevices(8),
pvchange(8), pvck(8), pvcreate(8), pvdisplay(8), pvmove(8),
pvremove(8), pvresize(8), pvs(8), pvscan(8),
vgcfgbackup(8), vgcfgrestore(8), vgchange(8), vgck(8),
vgcreate(8), vgconvert(8), vgdisplay(8), vgexport(8), vgextend(8),
vgimport(8), vgimportclone(8), vgimportdevices(8), vgmerge(8),
vgmknodes(8), vgreduce(8), vgremove(8), vgrename(8), vgs(8),
vgscan(8), vgsplit(8),
lvcreate(8), lvchange(8), lvconvert(8), lvdisplay(8), lvextend(8),
lvreduce(8), lvremove(8), lvrename(8), lvresize(8), lvs(8),
lvscan(8),
lvm-fullreport(8), lvm-lvpoll(8), blkdeactivate(8), lvmdump(8),
dmeventd(8), lvmpolld(8), lvmlockd(8), lvmlockctl(8), cmirrord(8),
lvmdbusd(8), fsadm(8),
lvmsystemid(7), lvmreport(7), lvmcache(7), lvmraid(7), lvmthin(7),
lvmvdo(7), lvmautoactivation(7)
This page is part of the lvm2 (Logical Volume Manager 2) project.
Information about the project can be found at
⟨http://www.sourceware.org/lvm2/⟩. If you have a bug report for
this manual page, see ⟨https://github.com/lvmteam/lvm2/issues⟩.
This page was obtained from the project's upstream Git repository
⟨git://sourceware.org/git/lvm2.git⟩ on 2025-08-11. (At that time,
the date of the most recent commit that was found in the
repository was 2025-08-08.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
[email protected]
Red Hat, Inc. LVM TOOLS 2.03.35(2)-git (2025-07-30) LVCONVERT(8)
Pages that refer to this page: lvmraid(7), lvmthin(7), lvmvdo(7), lvchange(8), lvconvert(8), lvcreate(8), lvdisplay(8), lvextend(8), lvm(8), lvmconfig(8), lvmdevices(8), lvmdiskscan(8), lvm-fullreport(8), lvm-lvpoll(8), lvmpolld(8), lvreduce(8), lvremove(8), lvrename(8), lvresize(8), lvs(8), lvscan(8), pvchange(8), pvck(8), pvcreate(8), pvdisplay(8), pvmove(8), pvremove(8), pvresize(8), pvs(8), pvscan(8), vgcfgbackup(8), vgcfgrestore(8), vgchange(8), vgck(8), vgconvert(8), vgcreate(8), vgdisplay(8), vgexport(8), vgextend(8), vgimport(8), vgimportclone(8), vgimportdevices(8), vgmerge(8), vgmknodes(8), vgreduce(8), vgremove(8), vgrename(8), vgs(8), vgscan(8), vgsplit(8)
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