LVCREATE(8)                                                        LVCREATE(8)



NAME
       lvcreate - create a logical volume in an existing volume group

SYNOPSIS
       lvcreate  [--addtag  Tag]  [--alloc  AllocationPolicy] [-A|--autobackup
       y|n] [-C|--contiguous y|n]  [-d|--debug]  [-h|-?|--help]  [-i|--stripes
       Stripes  [-I|--stripesize StripeSize]] {-l|--extents LogicalExtentsNum-
       ber[%{VG|PVS|FREE}] |
        -L|--size LogicalVolumeSize[kKmMgGtT]} [-M|--persistent y|n]  [--minor
       minor]   [-m|--mirrors  Mirrors  [--nosync]  [--mirrorlog  {disk|core}]
       [--corelog]  [-R|--regionsize  MirrorLogRegionSize]]  [-n|--name  Logi-
       calVolumeName]  [-p|--permission  r|rw]  [-r|--readahead  ReadAheadSec-
       tors|auto|none] [-t|--test] [-v|--verbose] [-Z|--zero y|n] VolumeGroup-
       Name [PhysicalVolumePath...]

       lvcreate {-l|--extents LogicalExtentsNumber[%{VG|FREE}] |
        -L|--size   LogicalVolumeSize[kKmMgGtT]}   [-c|--chunksize  ChunkSize]
       -s|--snapshot -n|--name  SnapshotLogicalVolumeName  OriginalLogicalVol-
       umePath

DESCRIPTION
       lvcreate  creates  a  new logical volume in a volume group ( see vgcre-
       ate(8), vgchange(8) ) by allocating logical extents from the free phys-
       ical  extent  pool  of that volume group.  If there are not enough free
       physical extents then the volume group can  be  extended  (  see  vgex-
       tend(8)  )  with other physical volumes or by reducing existing logical
       volumes of this volume group in size ( see lvreduce(8) ).
       The second form supports the creation of snapshot logical volumes which
       keep the contents of the original logical volume for backup purposes.

OPTIONS
       See lvm for common options.

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

       -C, --contiguous y|n
              Sets or resets the contiguous allocation policy for logical vol-
              umes.  Default  is no contiguous allocation based on a next free
              principle.

       -i, --stripes Stripes
              Gives the number of stripes.  This is equal  to  the  number  of
              physical volumes to scatter the logical volume.

       -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.

       -l, --extents LogicalExtentsNumber[%{VG|PVS|FREE}]
              Gives the number of logical extents to allocate for the new log-
              ical  volume.  This can also be expressed as a percentage of the
              total space in the Volume Group with  the  suffix  %VG,  of  the
              remaining  free space in the Volume Group with the suffix %FREE,
              or of the remaining free space for  the  specified  PhysicalVol-
              ume(s) with the suffix %PVS,

       -L, --size LogicalVolumeSize[kKmMgGtTpPeE]
              Gives  the  size to allocate for the new logical volume.  A size
              suffix of K for kilobytes, M for megabytes, G for  gigabytes,  T
              for terabytes, P for petabytes or E for exabytes is optional.
              Default unit is megabytes.

       --minor minor
              Set the minor number.

       -M, --persistent y|n
              Set to y to make the minor number specified persistent.

       -m, --mirrors Mirrors
              Creates  a  mirrored  logical  volume  with Mirrors copies.  For
              example, specifying "-m 1" would result in a  mirror  with  two-
              sides; that is, a linear volume plus one copy.

              Specifying  the  optional  argument --nosync will cause the cre-
              ation of the mirror to skip the initial resynchronization.   Any
              data  written afterwards will be mirrored, but the original con-
              tents will not be copied.  This is useful for skipping a  poten-
              tially  long  and  resource  intensive  initial sync of an empty
              device.

              The optional argument --mirrorlog specifies the type of  log  to
              be  used.  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. Using core means the mirror is
              regenerated by copying the data from the first device again each
              time the device is activated, for example, after every reboot.

              The  optional  argument  --corelog  is equivalent to --mirrorlog
              core.


       -n, --name LogicalVolumeName
              The name for the new logical volume.
              Without this option a default names of "lvol#" will be generated
              where # is the LVM internal number of the logical volume.

       -p, --permission r|rw
              Set access permissions to read only or read and write.
              Default is read and write.

       -r, --readahead ReadAheadSectors|auto|none
              Set  read ahead sector count of this logical volume.  For volume
              groups with metadata in  lvm1  format,  this  must  be  a  value
              between 2 and 120.  The default value is "auto" which allows the
              kernel to choose a  suitable  value  automatically.   "None"  is
              equivalent to specifying zero.

       -R, --regionsize MirrorLogRegionSize
              A  mirror  is divided into regions of this size (in MB), and the
              mirror log uses this granularity to track which regions  are  in
              sync.

       -s, --snapshot
              Create  a snapshot logical volume (or snapshot) for an existing,
              so called original logical volume (or origin).   Snapshots  pro-
              vide  a  'frozen  image' of the contents of the origin while the
              origin can still be updated. They enable consistent backups  and
              online  recovery of removed/overwritten data/files. The snapshot
              does not need the same amount of storage the origin  has.  In  a
              typical  scenario,  15-20% might be enough. In case the snapshot
              runs out of storage, use lvextend(8) to  grow  it.  Shrinking  a
              snapshot  is  supported by lvreduce(8) as well. Run lvdisplay(8)
              on the snapshot in order to check how much data is allocated  to
              it.

       -Z, --zero y|n
              Controls zeroing of the first KB of data in the new logical vol-
              ume.
              Default is yes.
              Volume will not be zeroed if read only flag is set.
              Snapshot volumes are zeroed always.

              Warning: trying to mount an unzeroed logical  volume  can  cause
              the system to hang.

Examples
       "lvcreate  -i  3  -I  8 -L 100M vg00" tries to create a striped logical
       volume with 3 stripes, a stripesize of 8KB and a size of 100MB  in  the
       volume  group  named  vg00.  The  logical volume name will be chosen by
       lvcreate.

       "lvcreate -m1 -L 500M vg00" tries to create  a  mirror  logical  volume
       with  2  sides  with  a  useable size of 500 MiB.  This operation would
       require 3 devices - two for the mirror devices and  one  for  the  disk
       log.

       "lvcreate  -m1  --mirrorlog core -L 500M vg00" tries to create a mirror
       logical volume with 2 sides with a useable size of 500 MiB.  This oper-
       ation would require 2 devices - the log is "in-memory".

       "lvcreate --size 100m --snapshot --name snap /dev/vg00/lvol1"
       creates a snapshot logical volume named /dev/vg00/snap which has access
       to the contents of the original logical volume named /dev/vg00/lvol1 at
       snapshot  logical  volume creation time. If the original logical volume
       contains a file system, you can mount the snapshot logical volume on an
       arbitrary  directory  in order to access the contents of the filesystem
       to run a backup while the original filesystem continues to get updated.


SEE ALSO
       lvm(8), vgcreate(8), lvremove(8), lvrename(8) lvextend(8), lvreduce(8),
       lvdisplay(8), lvscan(8)



Sistina Software UK    LVM TOOLS 2.02.44-cvs (02-17-09)            LVCREATE(8)

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