Disk group split and join


Disk group split and join
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Note:

You may need an additional license to use these features.

A snapshot volume can be split off into a separate disk group and deported. It is then ready for importing on another host that is dedicated to off-host processing. At a later stage, the disk group can be deported, re-imported, and joined with the original disk group or with a different disk group.

The split and join operations allow you to move VxVM objects such as disks or top-level volumes from one disk group to another.

The split operation is illustrated in Figure: Disk group split operation.

Figure: Disk group split operation

The join operation allows you to remove all VxVM objects from an imported disk group and move them to an imported target disk group. The source disk group is removed when the join is complete.

The join operation is illustrated in Figure: Disk group join operation .

Figure: Disk group join operation

Caution:

Before moving volumes between disk groups, you must stop all applications that are accessing the volumes and unmount all file systems that are configured in the volumes.

If the system crashes or a hardware subsystem fails, VxVM attempts to complete or reverse an incomplete disk group reconfiguration when the system is restarted or the hardware subsystem is repaired, depending on how far the reconfiguration had progressed. If one of the disk groups is no longer available because it has been imported by another host or because it no longer exists, you must recover the disk group manually.

The disk group move, split and join features have the following limitations:

Disk groups involved in a move, split or join must be version 90 or greater. If needed, you can upgrade your volume. Refer to the Veritas Volume Manager Administrator's Guide.
The reconfiguration must involve an integral number of physical disks.
Objects to be moved must not contain open volumes.
Moved volumes are initially disabled following a disk group move, split or join. If required, use either vxrecover -m or vxvol startall to restart the volumes.
Data change objects (DCOs) and snap objects that have been dissociated by persistent FastResync cannot be moved between disk groups.
Veritas Volume Replicator (VVR) objects cannot be moved between disk groups.
For a disk group move to succeed, the source disk group must contain at least one disk that can store copies of the configuration database after the move.
For a disk group split to succeed, both the source and target disk groups must contain at least one disk that can store copies of the configuration database after the split.
For a disk group move or join to succeed, the configuration database in the target disk group must be able to accommodate information about all the objects in the enlarged disk group.
Splitting or moving a volume into a different disk group changes the volume's record ID.

For more information, see the Veritas Volume Manager Administrator's Guide.

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