NAME¶
lvconvert — convert a logical volume from linear to mirror or snapshot
SYNOPSIS¶
lvconvert -m|
--mirrors Mirrors [
--type
SegmentType] [
--mirrorlog
{
disk|
core|
mirrored}] [
--corelog]
[
-R|
--regionsize MirrorLogRegionSize] [
--stripes
Stripes [
-I|
--stripesize StripeSize]]
[
-A|
--alloc AllocationPolicy]
[
-b|
--background] [
-f|
--force]
[
-i|
--interval Seconds] [
--commandprofile
ProfileName] [
-h|
-?|
--help] [
--noudevsync]
[
-v|
--verbose] [
-y|
--yes] [
--version]
LogicalVolume[
Path]
[
PhysicalVolume[
Path][
:PE[
-PE]]...]
lvconvert --splitmirrors Images [
--name
SplitLogicalVolumeName] [
--trackchanges]
MirrorLogicalVolume[
Path] [
--commandprofile
ProfileName]
[
SplittablePhysicalVolume[
Path][
:PE[
-PE]]...]
lvconvert --splitsnapshot [
--commandprofile
ProfileName] [
-h|
-?|
--help] [
--noudevsync]
[
-v|
--verbose] [
--version]
SnapshotLogicalVolume[
Path]
lvconvert -s|
--snapshot [
-c|
--chunksize
ChunkSize[
bBsSkK]] [
-Z|
--zero {
y|
n}]
[
--commandprofile ProfileName]
[
-h|
-?|
--help] [
--noudevsync]
[
-v|
--verbose] [
--version]
OriginalLogicalVolume[
Path]
SnapshotLogicalVolume[
Path]
lvconvert --merge [
-b|
--background]
[
-i|
--interval Seconds] [
--commandprofile
ProfileName] [
-h|
-?|
--help]
[
-v|
--verbose] [
--version]
LogicalVolume[
Path]...
lvconvert --repair [
--stripes Stripes
[
-I|
--stripesize StripeSize]] [
--commandprofile
ProfileName] [
-h|
-?|
--help]
[
-v|
--verbose] [
--version]
LogicalVolume[
Path] [
PhysicalVolume[
Path]...]
lvconvert --replace PhysicalVolume [
--commandprofile
ProfileName] [
-h|
-?|
--help]
[
-v|
--verbose] [
--version]
LogicalVolume[
Path] [
PhysicalVolume[
Path]...]
lvconvert [{
--type
thin[-pool]|-T|--thin}
[
--originname NewExternalOriginVolumeName]] [
--thinpool
ThinPoolLogicalVolume{
Name|
Path}
[
-c|
--chunksize ChunkSize[
bBsSkKmMgG]]
[
--discards {
ignore|
nopassdown|
passdown}]
[{
--poolmetadata
ThinPoolMetadataLogicalVolume{
Name|
Path} |
--poolmetadatasize ThinPoolMetadataSize[
bBsSkKmMgG]}]
[
-r|
--readahead
{
ReadAheadSectors|
auto|
none}]
[
--stripes Stripes
[
-I|
--stripesize StripeSize]]]
[
--poolmetadataspare {
y|
n}]
[
-Z|
--zero {
y|n}]]
[[
ExternalOrigin|
ThinPool]
LogicalVolume{
Name|
Path}]
[
PhysicalVolume[
Path][
:PE [
-PE]]...]
[
--commandprofile ProfileName]
[
-h|
-?|
--help] [
-v|
--verbose]
[
--version]
lvconvert [
--type
cache[-pool]|--cache]
[
--cachepool CachePoolLV{
Name|
Path}]
[
-c|
--chunksize ChunkSize[
bBsSkKmMgG]]
[
--cachemode {
writeback|
writethrough}]
[{
--poolmetadata
CachePoolMetadataLogicalVolume{
Name|
Path} |
--poolmetadatasize CachePoolMetadataSize[
bBsSkKmMgG]}]
[
--poolmetadataspare {
y|
n}]
LogicalVolume{
Name|
Path}
[
PhysicalVolume[
Path][
:PE[
-PE]]...]
[
--commandprofile ProfileName]
[
-h|
-?|
--help] [
-v|
--verbose]
[
--version]
DESCRIPTION¶
lvconvert is used to change the segment type (i.e. linear, mirror, etc) or
characteristics of a logical volume. For example, it can add or remove the
redundant images of a logical volume, change the log type of a mirror, or
designate a logical volume as a snapshot repository.
If the conversion requires allocation of physical extents (for example, when
converting from linear to mirror) and you specify one or more PhysicalVolumes
(optionally with ranges of physical extents), allocation of physical extents
will be restricted to these physical extents. If the conversion frees physical
extents (for example, when converting from a mirror to a linear, or reducing
mirror legs) and you specify one or more PhysicalVolumes, the freed extents
come first from the specified PhysicalVolumes.
OPTIONS¶
See
lvm(8) for common options.
Exactly one of
--cache,
--corelog,
--merge,
--mirrorlog,
--mirrors,
--repair,
--replace,
--splitsnapshot,
--snapshot,
--splitmirrors,
--thin or
--type arguments is required.
- -b, --background
- Run the daemon in the background.
- --cache, --type cache
- Converts logical volume to a cached LV with the use of cache pool
specified with --cachepool. For more information on cache pool LVs
and cache LVs, see lvmcache(8).
- --cachepool CachePoolLV
- This argument is necessary when converting a logical volume to a cache LV.
For more information on cache pool LVs and cache LVs, see
lvmcache(8).
- -m, --mirrors Mirrors
- Specifies the degree of the mirror you wish to create. For example, "
-m 1" would convert the original logical volume to a mirror
volume with 2-sides; that is, a linear volume plus one copy. There are two
implementations of mirroring which correspond to the "
raid1" and " mirror" segment types. The
default mirroring segment type is " raid1". If the legacy
" mirror" segment type is desired, the --type
argument must be used to explicitly select the desired type. The
--mirrorlog and --corelog options below are only relevant to
the legacy " mirror" segment type.
- --mirrorlog
{disk|core|mirrored}
- Specifies the type of log to use. 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 -
perhaps, for example, after every reboot. Using mirrored will
create a persistent log that is itself mirrored.
- --corelog
- The optional argument --corelog is the same as specifying
--mirrorlog core.
- -R, --regionsize MirrorLogRegionSize
- A mirror is divided into regions of this size (in MB), and the mirror log
uses this granularity to track which regions are in sync.
- --type SegmentType
- Used to convert a logical volume to another segment type, like
cache, cache-pool, raid1, snapshot,
thin, or thin-pool. When converting a logical volume to a
cache LV, the --cachepool argument is required. When converting a
logical volume to a thin LV, the --thinpool argument is required.
See lvmcache(7) for more info about caching support and
lvmthin(7) for thin provisioning support.
- -i, --interval Seconds
- Report progress as a percentage at regular intervals.
- --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 LVM2 creates.
- --splitmirrors Images
- The number of redundant Images of a mirror to be split off and used
to form a new logical volume. A name must be supplied for the
newly-split-off logical volume using the --name argument, unless
the --trackchanges argument is given.
- -n, --name Name
- The name to apply to a logical volume which has been split off from a
mirror logical volume.
- --trackchanges
- Used with --splitmirrors on a raid1 device, this tracks changes so
that the read-only detached image can be merged efficiently back into the
mirror later. Only the regions of the detached device where the data
changed get resynchronized.
Please note that this feature is only supported with the new md-based mirror
implementation and not with the original device-mapper mirror
implementation.
- --splitsnapshot
- Separates SnapshotLogicalVolume from its origin. The volume that is
split off contains the chunks that differ from the origin along with the
metadata describing them. This volume can be wiped and then destroyed with
lvremove. The inverse of --snapshot.
- -s, --snapshot, --type snapshot
- Recreates a snapshot from constituent logical volumes (or copies of them)
after having been separated using --splitsnapshot. For this to work
correctly, no changes may be made to the contents of either volume after
the split.
- -c, --chunksize
ChunkSize[bBsSkKmMgG]
- Gives the size of chunk for snapshot, cache pool and thin pool logical
volumes. Default unit is in kilobytes.
For snapshots the value must be power of 2 between 4KiB and 512KiB and the
default value is 4.
For cache pools the value must be between 32KiB and 1GiB and the default
value is 64.
For thin pools 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 weren't supported for
non-power of 2 values until thin target version 1.5.)
- --discards
{ignore|nopassdown|passdown}
- Specifies whether or not discards will be processed by the thin layer in
the kernel and passed down to the Physical Volume. Default is
passdown.
- -Z, --zero
{y|n}
- Controls zeroing of the first 4KiB of data in the snapshot. If the volume
is read-only the snapshot will not be zeroed. For thin pool volumes it
controls zeroing of provisioned blocks. Note: Provisioning of large zeroed
chunks negatively impacts performance.
- --merge
- Merges a snapshot into its origin volume or merges a raid1 image that has
been split from its mirror with --trackchanges back into its
mirror.
To check if your kernel supports the snapshot merge feature, look for
'snapshot-merge' in the output of dmsetup targets. If both the
origin and snapshot volume are not open the merge will start immediately.
Otherwise, the merge will start the first time either the origin or
snapshot 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 logical volume will have the origin's name, minor number and
UUID. While the merge is in progress, reads or writes to the origin appear
as they were directed to the snapshot being merged. When the merge
finishes, the merged snapshot is removed. Multiple snapshots may be
specified on the commandline or a @tag may be used to specify multiple
snapshots be merged to their respective origin.
- --originname NewExternalOriginVolumeName
- The new name for original logical volume, which becomes external origin
volume for a thin logical volume that will use given --thinpool.
Without this option a default name of "lvol<n>" will be
generated where <n> is the LVM internal number of the logical
volume. This volume will be read-only and cannot be further modified as
long, as it is being used as the external origin.
- --poolmetadata
ThinPoolMetadataLogicalVolume{Name|Path}
- Specifies cache or thin pool metadata logical volume. The size should be
in between 2MiB and 16GiB. Cache pool is specified with the option
--cachepool. Thin pool is specified with the option
--thinpool. When the specified pool already exists, the pool's
metadata volume will be swapped with the given LV. Pool properties (like
chunk size, discards or zero) are preserved by default in this case. It
can be useful for pool metadata repair or its offline resize, since the
metadata volume is available as regular volume for a user with thin
provisioning tools cache_dump(8), cache_repair(8),
cache_restore(8), thin_dump(8), thin_repair(8) and
thin_restore(8).
- --poolmetadatasize
ThinPoolMetadataSize[
bBsSkKmMgG]
- Sets the size of thin pool's metadata logical volume, if the pool metadata
volume is undefined. Thin pool is specified with the option
--thinpool. Supported value is in the range between 2MiB and 16GiB.
The default value is estimated with this formula (Pool_LV_size /
Pool_LV_chunk_size * 64b). Default unit is megabytes.
- --poolmetadataspare
{y|n}
- Controls creation and maintanence of pool metadata spare logical volume
that will be used for automated pool recovery. Only one such volume is
maintained within a volume group with the size of the biggest pool
metadata volume. Default is yes.
- -r, --readahead
{ReadAheadSectors|auto|none}
- Sets read ahead sector count of thin pool metadata logical volume. The
default value is " auto" which allows the kernel to
choose a suitable value automatically. " None" is
equivalent to specifying zero.
- --repair
- Repair a mirror after suffering a disk failure or try to fix thin pool
metadata.
The mirror will be brought back into a consistent state. By default, the
original number of mirrors will be restored if possible. Specify -y
on the command line to skip the prompts. Use -f if you do not want
any replacement. Additionally, you may use --use-policies to use
the device replacement policy specified in lvm.conf(5), viz.
activation/mirror_log_fault_policy or
activation/mirror_device_fault_policy.
Thin pool repair automates the use of thin_repair(8) tool. Only
inactive thin pool volumes can be repaired. There is no validation of
metadata between kernel and lvm2. This requires further manual work. After
successfull repair the old unmodified metadata are still available in
"<pool>_meta<n>" LV.
- --replace PhysicalVolume
- Remove the specified device (PhysicalVolume) and replace it with
one that is available in the volume group or from the specific list
provided. This option is only available to RAID segment types (e.g.
raid1, raid5, etc).
- --stripes Stripes
- Gives the number of stripes. This is equal to the number of physical
volumes to scatter the logical volume. This does not apply to existing
allocated space, only newly allocated space can be striped.
- -I, --stripesize StripeSize
- Gives the number of kilobytes for the granularity of the stripes.
StripeSize must be 2^n (n = 2 to 9) for metadata in LVM1 format. For
metadata in LVM2 format, the stripe size may be a larger power of 2 but
must not exceed the physical extent size.
- -T, --thin,
--type thin
- Converts the logical volume into a thin logical volume of the thin pool
specified with --thinpool. The original logical volume
ExternalOriginLogicalVolume is renamed into a new read-only logical
volume. For the non-default name for this volume use --originname.
The volume cannot be further modified as long as it is used as an external
origin volume for unprovisioned areas of any thin logical volume.
- --thinpool
ThinPoolLogicalVolume{Name|Path}
- Specifies or converts logical volume into a thin pool's data volume.
Content of converted volume is lost. Thin pool's metadata logical volume
can be specified with the option --poolmetadata or allocated with
--poolmetadatasize. See lvmthin(7) for more info about thin
provisioning support.
Examples¶
Converts the linear logical volume "vg00/lvol1" to a two-way mirror
logical volume:
lvconvert -m1 vg00/lvol1
Converts the linear logical volume "vg00/lvol1" to a two-way RAID1
logical volume:
lvconvert --type raid1 -m1 vg00/lvol1
Converts a mirror with a disk log to a mirror with an in-memory log:
lvconvert --mirrorlog core vg00/lvol1
Converts a mirror with an in-memory log to a mirror with a disk log:
lvconvert --mirrorlog disk vg00/lvol1
Converts a mirror logical volume to a linear logical volume:
lvconvert -m0 vg00/lvol1
Converts a mirror logical volume to a RAID1 logical volume with the same number
of images:
lvconvert --type raid1 vg00/mirror_lv
Converts logical volume "vg00/lvol2" to snapshot of original volume
"vg00/lvol1":
lvconvert -s vg00/lvol1 vg00/lvol2
Converts linear logical volume "vg00/lvol1" to a two-way mirror, using
physical extents /dev/sda:0-15 and /dev/sdb:0-15 for allocation of new
extents:
lvconvert -m1 vg00/lvol1 /dev/sda:0-15 /dev/sdb:0-15
Converts mirror logical volume "vg00/lvmirror1" to linear, freeing
physical extents from /dev/sda:
lvconvert -m0 vg00/lvmirror1 /dev/sda
Merges "vg00/lvol1_snap" into its origin:
lvconvert --merge vg00/lvol1_snap
If "vg00/lvol1", "vg00/lvol2" and "vg00/lvol3" are
all tagged with "some_tag" each snapshot logical volume will be
merged serially, e.g.: "vg00/lvol1", then "vg00/lvol2",
then "vg00/lvol3". If --background were used it would start all
snapshot logical volume merges in parallel.
lvconvert --merge @some_tag
Extracts one image from the mirror, making it a new logical volume named
"lv_split". The mirror the image is extracted from is reduced
accordingly. If it was a 2-way mirror (created with '-m 1'), then the
resulting original volume will be linear.
lvconvert --splitmirrors 1 --name lv_split vg00/lvmirror1
A mirrored logical volume created with --type raid1 can use the --trackchanges
argument when splitting off an image. Detach one image from the mirrored
logical volume lv_raid1 as a separate read-only device and track the changes
made to the mirror while it is detached. The split-off device has a name of
the form lv_raid1_rimage_N, where N is a number, and it cannot be renamed.
lvconvert --splitmirrors 1 --trackchanges vg00/lv_raid1
Merge an image that was detached temporarily from its mirror with the
--trackchanges argument back into its original mirror and bring its contents
back up-to-date.
lvconvert --merge vg00/lv_raid1_rimage_1
Replaces the physical volume "/dev/sdb1" in the RAID1 logical volume
"my_raid1" with the specified physical volume "/dev/sdf1".
Had the argument "/dev/sdf1" been left out, lvconvert would attempt
to find a suitable device from those available in the volume group.
lvconvert --replace /dev/sdb1 vg00/my_raid1 /dev/sdf1
Convert the logical volume "vg00/lvpool" into a thin pool with chunk
size 128KiB and convert "vg00/lv1" into a thin volume using this
pool. Original "vg00/lv1" is used as an external read-only origin,
where all writes to such volume are stored in the "vg00/lvpool".
lvconvert --type thin --thinpool vg00/lvpool -c 128 lv1
Convert the logical volume "vg00/origin" into a thin volume from the
thin pool "vg00/lvpool". This thin volume will use
"vg00/origin" as an external origin volume for unprovisioned areas
in this volume. For the read-only external origin use the new name
"vg00/external".
lvconvert -T --thinpool vg00/lvpool --originname external vg00/origin
Convert an existing logical volume to a cache pool LV using the given cache
metadata LV.
lvconvert --type cache-pool --poolmetadata vg00/lvx_meta vg00/lvx_data
lvrename vg00/lvx_data vg00/lvx_cachepool
Convert an existing logical volume to a cache LV using the given cache pool LV.
lvconvert --cache --cachepool vg00/lvx_cachepool vg00/lvx
SEE ALSO¶
lvm(8),
lvm.conf(5),
lvmcache(7),
lvmthin(7),
lvdisplay(8),
lvextend(8),
lvreduce(8),
lvremove(8),
lvrename(8),
lvscan(8),
vgcreate(8),
cache_dump(8),
cache_repair(8),
cache_restore(8),
thin_dump(8),
thin_repair(8),
thin_restore(8)