lvcreate



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 |
        -L/--size LogicalVolumeSize[kKmMgGtT]} [-M/--persistent y/n]  [--minor
       minor]    [-n/--name    LogicalVolumeName]    [-p/--permission    r/rw]
       [-r/--readahead ReadAheadSectors] [-t/--test] [-v/--verbose] [-Z/--zero
       y/n] VolumeGroupName [PhysicalVolumePath...]

       lvcreate {-l/--extents LogicalExtentsNumber |
        -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 1024k.

       -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)

       -l, --extents LogicalExtentsNumber
              Gives the number of logical extents to allocate for the new log-
              ical volume.

       -L, --size LogicalVolumeSize[kKmMgGtT]
              Gives  the  size to allocate for the new logical volume.  A size
              suffix of K for kilobytes, M for megabytes, G for gigabytes or T
              for terabytes 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.

       -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/w
              Set access permissions to read only or read and write.
              Default is read and write.

       -r, --readahead ReadAheadSectors
              Set read ahead sector count of this logical volume  to  a  value
              between 2 and 120.  Ignored by device-mapper.

       -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.

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


Examples

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

       "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                       LVCREATE(8)

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