HP StorageWorks Snapshot XP user guide (T1713-96021, June 2006)

16 Snapshot XP functions
Snapshot XP pool volumes
Creating virtual volume management areas
To use Snapshot XP, you must create virtual volume (V-VOL) management areas. The V-VOL management
area is an important area for associating Snapshot XP S-VOLs (V-VOL) with pool-VOLs. The V-VOL
management area is automatically created when additional shared memory is installed. For more
information about shared memory requirements, see Table 5. To install additional shared memory,
contact your HP account support representative.
There are two areas in the V-VOL management area: pool management block and pool association
information. When creating pools or Snapshot XP pairs, the pool management block or pool association
information is stored in the V-VOL management area. Therefore, the V-VOL management area’s available
capacity decreases. When all the V-VOL management area’s capacity is used, the capacity ratio of the
pool management block and pool association information in the V-VOL management area is fixed. If the
pool management block’s capacity is insufficient, problems might occur. For example, you cannot create
pools or pools with a large capacity. To solve such problems, initialize the V-VOL management area. For
more information, see ”Initializing V-VOL management areas or pool management blocks” on page 48.
Creating pools
A pool is an area where the snapshot data that Snapshot XP obtains is stored. A pool consists of multiple
pool-VOLs, and snapshot data is stored in a pool-VOL. You can register 1,024 pool-VOLs in a pool. You
Maximum number 8,191
For more information about the maximum number of Snapshot XP pairs you can create, see
”Calculating the number of Snapshot XP pairs you can create” on page 22.
Path definition Required
Table 3 Requirements for Snapshot XP S-VOLs (continued)
Item Requirement
Table 4 Requirements for Snapshot XP pool-VOLs
Item Requirement
Volume type Logical volume (LDEV)
You cannot specify the following volumes as Snapshot XP pool-VOLs:
• LUSE volumes
• Volumes used as a Snapshot XP pair’s P-VOL or S-VOL
• Volumes used by another software product’s pair or migration plan
• Volumes set with the Protect or Read Only attribute, or set to the S-VOL Disable setting
by LUN Security XP Extension
• NAS volumes
Emulation type OPEN-V
Maximum number 131,072
However, the maximum number of pool-VOLs that can be registered in each pool is 1,024.
In addition, a volume already registered as a pool-VOL in a pool cannot be registered in
another pool.
Path definition Not required
Volumes with path definitions cannot be specified as pool-VOLs.