NAME
       lvconvert - convert a logical volume from linear to mirror or snapshot

SYNOPSIS
       lvconvert   -m|--mirrors   Mirrors  [--mirrorlog  {disk|core|mirrored}]
       [--corelog] [-R|--regionsize MirrorLogRegionSize]  [-A|--alloc  Alloca-
       tionPolicy]   [-b|--background]  [-f|--force]  [-i|--interval  Seconds]
       [-h|-?|--help]   [--stripes   Stripes   [-I|--stripesize   StripeSize]]
       [--noudevsync] [-v|--verbose] [-y|--yes] [--version]
       LogicalVolume[Path] [PhysicalVolume[Path][:PE[-PE]]...]

       lvconvert   --splitmirrors   Images   [--name   SplitLogicalVolumeName]
       [--trackchanges]
       MirrorLogicalVolume[Path] [SplittablePhysicalVolume[Path][:PE[-PE]]...]

       lvconvert   -s|--snapshot   [-c|--chunksize  ChunkSize]  [-h|-?|--help]
       [--noudevsync] [-v|--verbose] [-Z|--zero y|n] [--version]
       OriginalLogicalVolume[Path] SnapshotLogicalVolume[Path]

       lvconvert    --merge    [-b|--background]    [-i|--interval    Seconds]
       [-h|-?|--help] [-v|--verbose] [--version] LogicalVolume[Path]...

       lvconvert  --repair  [-h|-?|--help] [--stripes Stripes [-I|--stripesize
       StripeSize]]  [-v|--verbose]  [--version]  LogicalVolume[Path]  [Physi-
       calVolume[Path]...]

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),  alloca-
       tion  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  speci-
       fied PhysicalVolumes.

OPTIONS
       See lvm for common options.
       Exactly  one  of  --splitmirrors,  --mirrors,  --repair,  --snapshot or
       --merge arguments is required.

       -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.

       --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  regener-
              ated  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.

       -b, --background
              Run the daemon in the background.

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

       --noudevsync
              Disable  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
              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 detatched
              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.

       -s, --snapshot
              Create a snapshot from existing  logical  volume  using  another
              existing logical volume as its origin.

       -c, --chunksize ChunkSize
              Power of 2 chunk size for the snapshot logical volume between 4k
              and 512k.

       -Z, --zero y|n
              Controls zeroing of the first KB of data in  the  snapshot.   If
              the volume is read-only the snapshot will not be zeroed.

       --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 snap-
              shot 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.

       --repair
              Repair  a mirror after suffering a disk failure. The mirror will
              be brought back into a consistent state.  By default, the origi-
              nal  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, viz.
              activation/mirror_log_fault_policy       or      activation/mir-
              ror_device_fault_policy.

       --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.

Examples
       "lvconvert -m1 vg00/lvol1"
       converts the linear logical volume "vg00/lvol1"  to  a  two-way  mirror
       logical volume.

       "lvconvert --mirrorlog core vg00/lvol1"
       converts a mirror with a disk log to a mirror with an in-memory log.

       "lvconvert --mirrorlog disk vg00/lvol1"
       converts a mirror with an in-memory log to a mirror with a disk log.

       "lvconvert -m0 vg00/lvol1"
       converts a mirror logical volume to a linear logical volume.

       "lvconvert -s vg00/lvol1 vg00/lvol2"
       converts  logical  volume  "vg00/lvol2"  to snapshot of original volume
       "vg00/lvol1"

       "lvconvert -m1 vg00/lvol1 /dev/sda:0-15 /dev/sdb:0-15"
       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 -m0 vg00/lvmirror1 /dev/sda"
       converts mirror logical  volume  "vg00/lvmirror1"  to  linear,  freeing
       physical extents from /dev/sda.

       "lvconvert --merge vg00/lvol1_snap"
       merges "vg00/lvol1_snap" into its origin.

       "lvconvert --merge @some_tag"
       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 --splitmirrors 1 --name lv_split vg00/lvmirror1"
       Extract one image from the mirror, making it a new logical volume named
       "lv_split".   The mirror the image is extracted from is reduced accord-
       ingly.  If it was a 2-way  mirror  (created  with  '-m  1'),  then  the
       resulting original volume will be linear.

       "lvconvert --splitmirrors 1 --trackchanges vg00/lv_raid1"
       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  sepa-
       rate 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_rim-
       age_N, where N is a number, and it cannot be renamed.

       "lvconvert --merge vg00/lv_raid1_rimage_1"
       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.

SEE ALSO
       lvm(8),   vgcreate(8),  lvremove(8),  lvrename(8),  lvextend(8),  lvre-
       duce(8), lvdisplay(8), lvscan(8)

Red Hat, Inc        LVM TOOLS 2.02.88(2)-RHEL5 (2013-06-25)       LVCONVERT(8)