HP StorageWorks XP Remote Web Console Software - Manual (Page 11)

You need to create a pool when you use XP Snapshot. Pool-VOLs registered in a pool can be
added but cannot be deleted. In addition, all snapshot data in the pool must be deleted to delete
the pool itself.
WARNING! The capacity of a pool is equal to the total capacity of the pool-VOLs registered in
the pool. The status of the XP Snapshot pair will be PSUE (status when failure occurred) when the
usage rate of the pool exceeds the capacity of the pool as a result of writing data in the volume
of that pair. XP Snapshot data cannot be stored in the pool, and no new XP Snapshot pair can be
created. Read
“ Notes on Defining Pool Capacity” (page 40) , and ensure that there is sufficient
pool capacity.
To create a pool, use the Pool window of the Remote Web Console.
Creation of a Virtual Volume
A V-VOL is a virtual volume which does not have physical memory space. A V-VOL needs to be
created before you create an XP Snapshot pair, because you must use a V-VOL as the S-VOL of
an XP Snapshot pair.
The definition of a V-VOL cannot be released if the V-VOL is being used as the S-VOL of an XP
Snapshot pair. To release the definition, you must delete the XP Snapshot pair that uses the V-VOL.
CAUTION: If you are using HP-UX as a host server, remember the following when you execute
the command on V-VOLs in order to recognize the device from the host server:
•
If the device is already recognized by the host server, do not change its volumes to V-VOLs.
•
Before executing the command to recognize the device, create XP Snapshot pairs and store
snapshot data.
If you do not follow these precautions, an error may occur and the host server may be terminated.
When the host server is terminated because of the command to recognize the device, retry the
command by completing the following steps:
1. Force the command process and its parent process to terminate.
2. Create an XP Snapshot pair.
3. Store the snapshot data in the pool.
4. Execute the command again to recognize the device.
Servers (including RAID Manager) will indicate the emulation type of the V-VOLs with a 0 (for
example, OPEN-0V). When you create an XP Snapshot pair, specify the volume whose emulation
type includes 0, such as OPEN-0V, as the S-VOL.
Before creating a V-VOL, you need to define a V-VOL group. Like the emulation type of V-VOLs,
the emulation type of a VDEV for a V-VOL group is OPEN-V. In addition, the capacity of the VDEV
is always 4 TB. Therefore, the maximum capacity of a V-VOL is also 4 TB.
XP Snapshot Operations 11