plucky (8) lvconvert.8.gz

Provided by: lvm2_2.03.27-1ubuntu1_amd64 bug

NAME

       lvconvert — Change logical volume layout

SYNOPSIS

       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
           --integritysettings String
        -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
           --pooldatavdo y|n
           --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
        -k|--setactivationskip y|n
        -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
           --vdosettings String
        -v|--verbose
           --version
        -V|--virtualsize Size[m|UNIT]
        -W|--wipesignatures y|n
        -y|--yes
        -Z|--zero y|n

DESCRIPTION

       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 interchangeably.

       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 recovery 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  reasons,  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).  Additionally,  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. linear ↔ raid1 ↔ raid5_n (then adding stripes) ↔ striped/raid0/raid0_meta.

USAGE

       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 origin.

       lvconvert --type thin --thinpool LV LV1
           [ -T|--thin ]
           [ -c|--chunksize Size[k|UNIT] ]
           [ -r|--readahead auto|none|Number ]
           [ -W|--wipesignatures y|n ]
           [ -Z|--zero y|n ]
           [    --originname LV_new ]
           [    --poolmetadata LV ]
           [    --poolmetadatasize Size[m|UNIT] ]
           [    --poolmetadataspare y|n ]
           [    --metadataprofile String ]
           [ COMMON_OPTIONS ]
           [ PV ... ]

           LV1 types: linear striped cache raid thin zero error

       —

       Convert LV to a thin LV, using LV as thin-pool data volume.

       lvconvert --type thin LV1
           [ -T|--thin ]
           [ -c|--chunksize Size[k|UNIT] ]
           [ -r|--readahead auto|none|Number ]
           [ -W|--wipesignatures y|n ]
           [ -Z|--zero y|n ]
           [    --poolmetadata LV ]
           [    --poolmetadatasize Size[m|UNIT] ]
           [    --poolmetadataspare y|n ]
           [    --metadataprofile String ]
           [ COMMON_OPTIONS ]
           [ PV ... ]

           LV1 types: linear striped cache raid vdo writecache zero error

       —

       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 ]
           [ -c|--chunksize Size[k|UNIT] ]
           [ -r|--readahead auto|none|Number ]
           [ -W|--wipesignatures y|n ]
           [    --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 thin thinpool vdo vdopool vdopooldata zero error

       —

       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 raid thinpool

       —

       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 raid thinpool

       —

       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 raid thinpool

       —

       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 raid thinpool

       —

       Convert LV to type thin-pool.

       lvconvert --type thin-pool LV1
           [ -I|--stripesize Size[k|UNIT] ]
           [ -c|--chunksize Size[k|UNIT] ]
           [ -r|--readahead auto|none|Number ]
           [ -W|--wipesignatures y|n ]
           [ -Z|--zero y|n ]
           [    --stripes Number ]
           [    --discards passdown|nopassdown|ignore ]
           [    --errorwhenfull y|n ]
           [    --pooldatavdo y|n ]
           [    --compression y|n ]
           [    --deduplication y|n ]
           [    --vdosettings String ]
           [    --poolmetadata LV ]
           [    --poolmetadatasize Size[m|UNIT] ]
           [    --poolmetadataspare y|n ]
           [    --metadataprofile String ]
           [ COMMON_OPTIONS ]
           [ PV ... ]

           LV1 types: linear striped cache raid vdo writecache zero error

       —

       Convert LV to type cache-pool.

       lvconvert --type cache-pool LV1
           [ -Z|--zero y|n ]
           [ -c|--chunksize Size[k|UNIT] ]
           [ -r|--readahead auto|none|Number ]
           [ -W|--wipesignatures y|n ]
           [    --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 zero error

       —

       Convert LV to type vdopool.

       lvconvert --type vdo-pool LV1
           [ -n|--name LV_new ]
           [ -V|--virtualsize Size[m|UNIT] ]
           [ -r|--readahead auto|none|Number ]
           [ -W|--wipesignatures y|n ]
           [ -Z|--zero y|n ]
           [    --compression y|n ]
           [    --deduplication y|n ]
           [    --vdosettings String ]
           [    --metadataprofile String ]
           [ COMMON_OPTIONS ]

           LV1 types: linear striped cache raid

       —

       Detach a cache from an LV.

       lvconvert --splitcache LV1
           [    --cachesettings String ]
           [ COMMON_OPTIONS ]

           LV1 types: cache cachepool thinpool 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 ]
           [ -k|--setactivationskip y|n ]
           [    --usepolicies ]
           [    --poolmetadataspare y|n ]
           [ COMMON_OPTIONS ]
           [ PV ... ]

           LV1 types: cache cachepool mirror raid thinpool

       —

       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 ]
           [    --integritysettings String ]
           [ 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 ]

OPTIONS

       --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.  normal 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 existing PEs in the same
              stripe of the LV.  If there are sufficient PEs for an allocation, but normal does  not  use  them,
              anywhere will use them even if it reduces performance, e.g. by placing two stripes on the same PV.
              Optional 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
              invalidates. 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  kernel options for dm-cache or dm-writecache LVs.  Use the form 'option=value'
              or 'option1=value option2=value', or repeat --cachesettings for  each  option  being  set.   These
              settings override the default kernel behaviors which are usually adequate. To remove cachesettings
              and revert to the default kernel behaviors, use --cachesettings 'default' for dm-cache or an empty
              string --cachesettings '' for dm-writecache.  See lvmcache(7) for more information.

       --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 4 KiB and 512 KiB and the default value is 4.  For a cache pool the value  must
              be  between  32 KiB  and  1 GiB  and  the  default value is 64.  For a thin pool the value must be
              between 64 KiB and 1 GiB and the default value starts with 64  and  scales  up  to  fit  the  pool
              metadata  size  within  128 MiB,  if the pool metadata size is not specified.  The value must be a
              multiple of 64 KiB.  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 usage.

       --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
              Restricts the devices that are visible and accessible to the command.   Devices  not  listed  will
              appear  to  be missing. This option can be repeated, 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) devices/devicesfile and
              devices/use_devicesfile settings.

       --discards passdown|nopassdown|ignore
              Specifies how the device-mapper thin pool layer in the  kernel  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 information.

       --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.  Errors are returned if no space is available after the timeout.  (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.

       --integritysettings String
              Specifies tunable kernel options for dm-integrity.  See lvmraid(7) for more information.

       -i|--interval Number
              Report progress at regular intervals.

       --journal String
              Record information in the systemd journal.  This information 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.  debug: 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 --mergesnapshot, 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 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.

       --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  persistent  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 images of the data, the original and one mirror image.  Optional 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_default
              to  configure the default types.  The plus prefix + can be used, in which case the number is added
              to the current 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 default 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 command may read more devices to  find  PVs
              when  hints  are  not  used.  The command will still perform standard hint file invalidation where
              appropriate.

       --nolocking
              Disable locking. Use with caution, concurrent commands may produce incorrect results.

       --noudevsync
              Disables udev synchronization. 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 becomes a read-only external origin with this name.

       --pooldatavdo y|n
              Use VDO type volume for pool data volume.

       --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, depending 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 logical 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 areas 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 automatically.  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 configure 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.

       -k|--setactivationskip y|n
              Persistently sets (yes) or clears (no) the "activation skip" flag on an LV.  An LV with this  flag
              set  is  not activated unless the --ignoreactivationskip option is used by the activation command.
              This flag is set by default on new thin snapshot LVs.  The flag is not  applied  to  deactivation.
              The current value of the flag is indicated in the lvs lv_attr bits.

       -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  unused  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 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.  If --name is specified, then the images are permanently split from the original
              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 nevertheless 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 provisioning.

       --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 efficiently 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 permanently 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 performance (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 unused 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 information about VDO usage.

       --vdosettings String
              Specifies tunable VDO options  for  VDO  LVs.   Use  the  form  'option=value'  or  'option1=value
              option2=value',  or  repeat  --vdosettings for each option being set.  These settings override the
              default VDO behaviors.  To remove vdosettings  and  revert  to  the  default  VDO  behaviors,  use
              --vdosettings 'default'.  See lvmvdo(7) for more information.

       -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.   Anything 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 target, and the LV has the suffix _vorigin.
              Snapshots are less efficient than thin provisioning when creating large sparse LVs (GiB).

       -W|--wipesignatures y|n
              Controls detection and subsequent wiping of signatures on new LVs.  There is  a  prompt  for  each
              signature  detected  to confirm its wiping (unless --yes is used to override confirmations.)  When
              not specified, signatures are wiped whenever zeroing is done (see --zero). This behaviour  can  be
              configured  with  lvm.conf(5) allocation/wipe_signatures_when_zeroing_new_lvs.  If blkid wiping is
              used (lvm.conf(5) allocation/use_blkid_wiping) and LVM is compiled with blkid wiping support, then
              the  blkid(8)  library  is used to detect the signatures (use blkid -k to list the signatures that
              are recognized).  Otherwise, native LVM code is used to detect signatures (only MD RAID, swap  and
              LUKS signatures are detected in this case.)  The LV is not wiped if the read only flag is set.

       -y|--yes
              Do  not  prompt  for confirmation interactively but always assume the answer yes. Use with extreme
              caution.  (For automatic no, see -qq.)

       -Z|--zero y|n
              For snapshots, this controls zeroing of the first 4 KiB 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.

VARIABLES

       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 represents raid<N> type).

       PV     Physical Volume name, a device path under /dev.  For commands  managing  physical  extents,  a  PV
              positional  arg  generally  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.  Input 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.)

ENVIRONMENT VARIABLES

       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.

ADVANCED USAGE

       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 origin.

       lvconvert -T|--thin --thinpool LV LV1
           [ --type thin ] (implied)
           [ -c|--chunksize Size[k|UNIT] ]
           [ -r|--readahead auto|none|Number ]
           [ -W|--wipesignatures y|n ]
           [ -Z|--zero y|n ]
           [    --originname LV_new ]
           [    --poolmetadata LV ]
           [    --poolmetadatasize Size[m|UNIT] ]
           [    --poolmetadataspare y|n ]
           [    --metadataprofile String ]
           [ COMMON_OPTIONS ]
           [ PV ... ]

           LV1 types: linear striped cache raid thin zero error

       —

       Convert LV to a thin LV, using LV as thin-pool data volume.

       lvconvert -T|--thin LV1
           [ --type thin ] (implied)
           [ -c|--chunksize Size[k|UNIT] ]
           [ -r|--readahead auto|none|Number ]
           [ -W|--wipesignatures y|n ]
           [ -Z|--zero y|n ]
           [    --poolmetadata LV ]
           [    --poolmetadatasize Size[m|UNIT] ]
           [    --poolmetadataspare y|n ]
           [    --metadataprofile String ]
           [ COMMON_OPTIONS ]
           [ PV ... ]

           LV1 types: linear striped cache raid vdo writecache zero error

       —

       Attach a cache pool to an LV.

       lvconvert -H|--cache --cachepool LV LV1
           [ --type cache ] (implied)
           [ -Z|--zero y|n ]
           [ -c|--chunksize Size[k|UNIT] ]
           [ -r|--readahead auto|none|Number ]
           [ -W|--wipesignatures y|n ]
           [    --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 thin thinpool vdo vdopool vdopooldata zero error

       —

       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 raid thinpool

       —

       Convert LV to type vdopool.

       lvconvert --vdopool LV
           [ --type vdo-pool ] (implied)
           [ -r|--readahead auto|none|Number ]
           [ -W|--wipesignatures y|n ]
           [ -Z|--zero y|n ]
           [ -n|--name LV_new ]
           [ -V|--virtualsize Size[m|UNIT] ]
           [    --compression y|n ]
           [    --deduplication y|n ]
           [    --vdosettings String ]
           [    --metadataprofile String ]
           [ COMMON_OPTIONS ]

       —

       Detach and delete a cache from an LV.

       lvconvert --uncache LV1
           [    --cachesettings String ]
           [ COMMON_OPTIONS ]

           LV1 types: cache thinpool 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: cachepool thinpool

       —

       Merge LV that was split from a mirror (variant, use --mergemirrors).
       Merge thin LV into its origin LV (variant, use --mergethin).
       Merge COW snapshot LV into its origin (variant, use --mergesnapshot).

       lvconvert --merge VG|LV1|Tag ...
           [ -i|--interval Number ]
           [ COMMON_OPTIONS ]

           LV1 types: linear striped snapshot raid thin

       —

       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

       —

NOTES

       This previous command syntax would perform two different operations:
       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.)

EXAMPLES

       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 metadata size to 1GiB.
       lvconvert --type thin --poolmetadatasize 1G vg/lvol1

       Convert an LV into a thin-pool with VDO deduplication and compression 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 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
              --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

SEE ALSO

       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)