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Commands Reference, Volume 5

splitvg Command


Splits a single mirror copy of a fully mirrored volume group.


splitvg  [ -y SnapVGname ]  [ -c  Copy ] [ -f  ] [ -i ]  VGname 


The splitvg command splits a single mirror copy of a fully mirrored volume group into a snapshot volume group. The orginal volume group VGname will stop using the disks that are now part of the snapshot volume group SnapVGname. Both volume groups will keep track of the writes within the volume group so that when the snapshot volume group is rejoined with the original volume group consistent data is maintained across the rejoined mirrors copies.

  1. To split a volume group, all logical volumes in the volume group must have the target mirror copy and the mirror must exist on a disk or set of disks. Only the target mirror copy must exist on the target disk or disks.
  2. The splitvg command will fail if any of the disks to be split are not active within the orginal volume group.
  3. In the unlikely event of a system crash or loss of quorum while running this command, the joinvg command must be run to rejoin the disks back to the orginal volume group.
  4. There is no concurrent or enhanced concurrent mode support for creating snapshot volume groups.
  5. New logical volumes and file system mount points will be created in the snapshot volume group.


-y SnapVGname Allows the volume group name to be specified rather than having the name generated automatically. Volume group names must be unique across the system and can range from 1 to 15 characters. The name cannot begin with a prefix already defined in the PdDv class in the Device Configuration database for other devices. The new volume group name is sent to standard output.
-c Copy Which mirror to split. Valid values are 1, 2, or 3. The default is the second copy.
-f Will force the split even if the mirror copy specified to create the snashot volume group has stale partitions.
-i Will split the mirror copy of a volume group into a new volume group that can not be rejoined into the orginal.


Access Control: You must have root authority to run this command.


  1. To split a volume group, type:
    splitvg testvg

    The second mirror copy of the volume group testvg is split into new volume group with an automatically generated name, which will be displayed.

  2. To split first mirror copy of the volume group with the name snapvg, type:
    splitvg -y snapvg -c 1 testvg


/usr/sbin Directory where the splitvg command resides.

Related Information

The joinvg and recreatevg commands.

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