Importing or Exporting a Volume Group

The following procedure explains how to import and export a volume group. The import procedure is used to make the volume group known to a system after the group is exported and moved from another system. It is also used to "reintroduce" (make known to the system) a group that was previously used on the system but was exported. If the importvg command is not working correctly, refreshing the device configuration database may help. See "Synchronizing the Device Configuration Database".

The export steps remove the definition of a volume group from a system before the group is moved to a different system.

The procedures together can be used to move a volume group from one system to another.

You can also use this procedure to add a physical volume which contains data to a volume grou. You can do this by putting the disk to be added in its own volume group.

Note: The rootvg volume group cannot be exported or imported.

Among the reasons you would organize physical volumes into separate volume groups are the following:

• To separate user file systems from the operating system to facilitate system updates, reinstallations, and crash recoveries.
• To facilitate the moving of portable disks from one system to another.
• To allow removal of disks for security or maintenance reasons.
• To switch physical volumes between multiple system units.

  For more details, see "Developing a Volume Group Strategy".

Prerequisites

Be sure you read and understand the following articles before you import or export a volume group:

• importvg and exportvg commands
• "Logical Volume Storage Overview"

Attention: The importvg command changes the name of an imported logical volume if there currently is a logical volume with the same name already on the system. An error message is printed to standard error if an imported logical volume is renamed. The importvg command also creates file mount points and entries in /etc/filesystems if possible (if there are no conflicts).

Attention: A volume group that has a paging space volume on it cannot be exported while the paging space is active. Before exporting a volume group with an active paging space, ensure that the paging space is not activated automatically at system initialization by running the following command:

chps -a n paging_space name

Then, reboot the system so that the paging space is inactive.

Notes:

1. If you do not activate the volume group through smit importvg, you must run the varyonvg command to enable access to the file systems and logical volumes.
2. If you imported a volume group that contains file systems, or if you activated the volume group through smit importvg, it is highly recommended that you run the fsck command before you mount the file systems.
3. If you are moving the volume group to another system, be sure to unconfigure the disks before moving them.
4. The smit exportvg process deletes references to file systems in /etc/filesystems, but it leaves the mount points on the system.