reducevg Command

Purpose

Removes physical volumes from a volume group. When all physical volumes are removed from the volume group, the volume group is deleted.

Syntax

reducevg [  -d ] [  -f ] VolumeGroup PhysicalVolume ...

Description

Attention: You can use the reducevg command while the volume group is in concurrent mode. However, if you run this command while the volume group is in concurrent mode and the end result is the deletion of the volume group, then the reducevg command will fail.

The reducevg command removes one or more physical volumes represented by the PhysicalVolume parameter from the VolumeGroup. When you remove all physical volumes in a volume group, the volume group is also removed. The volume group must be varied on before it can be reduced.

All logical volumes residing on the physical volumes represented by the PhysicalVolume parameter must be removed with the rmlv command or the -d flag before starting the reducevg command.
Note:
  1. To use this command, you must either have root user authority or be a member of the system group.
  2. Sometimes a disk is removed from the system without first running reducevg VolumeGroup PhysicalVolume. The VGDA still has this removed disk in it's memory, but the PhysicalVolume name no longer exists or has been reassigned. To remove references to this missing disk you can still use reducevg, but with the Physical Volume ID (PVID) instead of the disk name: reducevg VolumeGroup PVID.
  3. You cannot use the reducevg command on a snapshot volume group.
  4. You cannot use the reducevg command on a volume group that has an active firmware assisted dump logical volume.

For volume groups created on AIX® 5.3 and varied on without the varyonvg -M flag, reducevg will dynamically raise the logical track group size for the volume group if necessary to match the common max transfer size of the remaining physical volumes.

You can use the Volumes application in Web-based System Manager (wsm) to change volume characteristics.

You could also use the System Management Interface Tool (SMIT) smit reducevg fast path to run this command.

See the section "Administering a PowerHA® cluster" in the PowerHA SystemMirror Administration Guide, 7.1 or later, for a discussion of the behavior of this command in a PowerHA cluster.

Flags

Item Description
-d Deallocates the existing logical volume partitions and then deletes resultant empty logical volumes from the specified physical volumes. User confirmation is required unless the -f flag is added.
Attention: The reducevg command with the -d flag automatically deletes all logical volume data on the physical volume before removing the physical volume from the volume group. If a logical volume spans multiple physical volumes, the removal of any of those physical volumes may jeopardize the integrity of the entire logical volume.
-f Removes the requirement for user confirmation when the -d flag is used.

Security

Attention RBAC users and Trusted AIX users: This command can perform privileged operations. Only privileged users can run privileged operations. For more information about authorizations and privileges, see Privileged Command Database in Security. For a list of privileges and the authorizations associated with this command, see the lssecattr command or the getcmdattr subcommand.

Examples

  1. To remove physical volume hdisk1 from volume group vg01, enter: 
    reducevg vg01 hdisk1
  2. To remove physical volume hdisk1 and all residing logical volumes from volume group vg01 without user confirmation, enter the following command. Attention: The reducevg command with the -d flag automatically deletes all logical volume data before removing the physical volume.

    reducevg  -d  -f vg01 hdisk1

    The physical volume hdisk1 and all residing logical volumes are removed.

Files

Item Description
/usr/sbin/reducevg Directory where the reducevg command resides.
/tmp Directory where the temporary files are stored and while the command is running.