Moving Disk Groups Between Systems

On the first system, stop all volumes in the disk group, then deport (disable local access to) the disk group with the following command:

		# vxdg
 deport diskgroup 

Move all the disks to the second system and perform the steps necessary (system-dependent) for the second system and Volume Manager to recognize the new disks.

This can require a reboot, in which case the vxconfigd daemon is restarted and recognizes the new disks. If you do not reboot, use the command vxdctl enable to restart the vxconfigd program so Volume Manager also recognizes the disks.

Import (enable local access to) the disk group on the second system with this command:

		# vxdg import diskgroup

	CAUTION: It is very important that all the disks in the disk group be moved to the other system. If they are not moved, the import will fail.

After the disk group is imported, start all volumes in the disk group with this command:

		# vxrecover -g diskgroup -sb  
 

You can also move disks from a system that has crashed. In this case, you cannot deport the disk group from the first system. When a disk group is created or imported on a system, that system writes a lock on all disks in the disk group.

	CAUTION: The purpose of the lock is to ensure that dual-ported disks (disks that can be accessed simultaneously by two systems) are not used by both systems at the same time. If two systems try to manage the same disks at the same time, configuration information stored on the disk is corrupted. The disk and its data become unusable.

When you move disks from a system that has crashed or failed to detect the group before the disk is moved, the locks stored on the disks remain and must be cleared. The system returns the this error message:

	vxdg:disk group groupname: import failed: Disk is in use by another
	host

To clear locks on a specific set of devices, use the following command:

# vxdisk clearimport devicename...

To clear the locks during import, use the following command:

# vxdg -C import diskgroup

	NOTE: Be careful when using the vxdisk clearimport or vxdg -C import command on systems that have dual-ported disks. Clearing the locks allows those disks to be accessed at the same time from multiple hosts and can result in corrupted data.

You may want to import a disk group when some disks are not available. The import operation fails if some disks for the disk group cannot be found among the disk drives attached to the system. When the import operation fails, one of several error messages is displayed.

The following message indicates a fatal error that requires hardware repair or the creation of a new disk group, and recovery of the disk group configuration and data.

	vxdg: Disk group groupname: import failed: Disk group has no valid
	configuration copies

The following message indicates a recoverable error.

	vxdg
: Disk group groupname: import failed: Disk for disk group not
	found

If some of the disks in the disk group have failed, force the disk group to be imported with the command:

# vxdg -f import diskgroup

	NOTE: Be careful when using the -f option. It can cause the same disk group to be imported twice from different sets of disks, causing the disk group to become inconsistent.

These operations can be performed using the vxdiskadm utility. To deport a disk group by using vxdiskadm, select menu item 9 (Remove access to (deport) a disk group). To import a disk group, select item 8 (Enable access to (import) a disk group). The vxdiskadm import operation checks for host import locks and prompts to see if you want to clear any that are found. It also starts volumes in the disk group.