Pools, V-vols, Growing a v-vol – HP StorageWorks XP Remote Web Console Software User Manual

Page 9: Pools v-vols

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Table 1 Supported XP Thin Provisioning Configurations (continued)

Supported Configurations

Items

1024 per pool

Maximum number of
pool-VOLs

8 GB to 4 TB

Capacity per Pool-VOL

Pools

XP Thin Provisioning requires the use of pools. A storage system supports up to 128 pools, each
of which can contain up to 1,024 pool-VOLs and 8,192 V-VOLs. Each pool requires a unique
pool ID.

XP Snapshot also uses pools. The 128-pool maximum per storage system applies to the total number
of both XP Snapshot pools and XP Thin Provisioning pools. For more information about XP Snapshot,
see the HP XP24000/XP20000 Snapshot User Guide.

The total pool capacity is the total capacity of the registered XP Thin Provisioning pool-VOLs.

Pool capacity is calculated by the following formula:

Total Number of pages = (

pool-VOL number of blocks

512

168 ) for each pool-VOL

The capacity of the pool (MB) = Total number of pages x 42 − (4116 + 84 x Number of
pool-VOLs)

: truncate the part of the formula between the arrows after the decimal point. If you increase

pool capacity by adding a pool-VOL, existing data in the pool automatically migrates from older
pool-VOLs to the newly added pool-VOL, balancing the usage levels of all pool-VOLs. If you do
not want to automate balancing of the usage levels of pool-VOLs, consult HP technical support (see

“Calling HP Technical Support” (page 80)

).

XP Thin Provisioning Software automatically balances the usage levels among pool-VOLs in the
pool created with microcode version 60-05-0x or later. XP Thin Provisioning Software does not
automatically balance the usage levels among pool-VOLs if the cache memory is not redundant or
if the pool usage level is more than the pool thresholds.

For more information about pools, including a description of the Pool window, see

“Pool Window”

(page 27)

. For instructions on managing pools, see

“Managing Pools” (page 52)

.

V-VOLs

XP Thin Provisioning requires the use of V-VOLs, which are virtual volumes with no physical memory
space. V-VOLs can be 46 MB to 4 TB.

To create a V-VOL, use the Remote Web Console V-VOL window (see

“V-VOL Window” (page 31)

).

OPEN-V is the only supported emulation type. You can define multiple V-VOLs and assign them as
V-VOLs to a storage pool. A V-VOL cannot be associated with more than one pool. For more
information, see

“V-VOL Window” (page 31)

and

“Managing V-VOLs and V-VOL Groups”

(page 57)

.

If the system option mode 726 is enabled, you can set only one V-VOL in one V-VOL group.
Therefore, the number of V-VOL groups that can be defined in the whole storage system is the
same as the number of LDEVs that can be defined in the whole storage system. For details on the
number of definable V-VOL groups in the whole system, see the explanation about the Copy of
V-VOL Groups number text box in the New V-VOL Group dialog box.

Growing a V-VOL

You can grow (dynamically increase the LUN capacity of) a V-VOL without migrating the data.
For instructions, see

“Increasing V-VOL Capacity” (page 62)

.

XP Thin Provisioning Components

9

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