HP XP20000XP24000 Disk Array - Manual (Page 17)

Creating the V-VOL Management Area
Before you can use XP Thin Provisioning, you must have a V-VOL management area, which is used to
associate a V-VOL with a pool-VOL. The V-VOL management area is created automatically when the
required additional shared memory is installed by your HP service representative.
Creating Pools
A pool consists of one or more pool-VOLs. 256 pool-VOLs can be registered in a pool, and 32 pools can
be created in a storage system. You need to create a pool when you use XP Thin Provisioning. Pool-VOLs
can be added to a pool, but cannot be deleted during operations. In addition, all of the data in the pool
needs to be deleted if you want to delete the pool itself.
You need to set a pool ID for every pool. A pool can be associated with multiple V-VOLs. You can
store multiple pool-VOLs in a pool. XP Thin Provisioning pools cannot be used as HP StorageWorks XP
Snapshot pools, or vice versa.
Warning:
• The capacity of the pool is calculated by the following formulas:
The capacity of the pool (MB) = total page number Ч 42 − (4116 + 84 Ч pool-VOL number)
Total page number = Σ(↓↓block number of pool-VOL ч 512↓ ч 168↓)
↓ ↓ : Truncate the part of the formula between the arrows after the decimal point.
• XP Thin Provisioning pools cannot be used as XP Snapshot pools. The maximum total number
of XP Snapshot pools and XP Thin Provisioning pools is 32. For more information about XP
Snapshot, see HP StorageWorks XP24000 Snapshot User's Guide.
To create a pool, use the Pool window of Remote Web Console. For details about the Pool window,
see “ Pool Window ” on page 33. For details about how to create a pool and how to add a pool-VOL,
see “ Managing Pools ” on page 44.
Creating V-VOLs
A V-VOL is a virtual volume that does not have physical memory space. A V-VOL needs to be created
before using XP Thin Provisioning.
To create a V-VOL, use the V-VOL window of Remote Web Console. You need to specify the pool ID,
V-VOL capacity, and LDEV number. You can specify only OPEN-V as the emulation type. Unlike XP
Snapshot V-VOLs, XP Thin Provisioning V-VOLs need to be associated with a pool. For details about the
V-VOL window, see “ V-VOL Window ” on page 36. For details about how to create a V-VOL, see
“ Managing V-VOLs ” on page 48.
XP Thin Provisioning allows you to create multiple V-VOLs.
Once a V-VOL contains data, you cannot increase the capacity of that V-VOL. You must instead delete
that V-VOL and create a new one with a larger capacity.
Associating V-VOLs with a Pool
It is necessary to associate XP Thin Provisioning V-VOLs with a pool. When V-VOLs and a pool are not
associated, the host system cannot use the V-VOLs because they have no path definition. Also, if the path
definitions of the V-VOLs are not deleted, the association between V-VOLs and a pool cannot be released.
Also, one or more V-VOLs can be associated with a pool. However, you cannot associate a V-VOL
with multiple pools.
Monitoring the Available Pool Capacity
One of the key features of XP Thin Provisioning is that you can define V-VOLs that have a greater capacity
than the pool capacity. However, if you run out of free space in a pool, the host cannot access data. It is
therefore essential to closely monitor pool capacity, so that you can increase it as needed.
XP24000 Thin Provisioning Software User's Guide 17