HP XP7 Cache Partition User Guide (H6F56-96002)

Internal volume capacity =

(number of (3D+1P) parity groups) × (capacity of one drive) × 3 +

(number of (6D+2P) parity groups) × (capacity of one drive) × 6 +

(number of (7D+1P) parity groups) × (capacity of one drive) × 7 +

(number of (14D+2P) parity groups) × (capacity of one drive) × 14

+ (number of (2D+2D) parity groups) × (capacity of one drive) × 2

Do not use this formula for an external volume or virtual volume.

Formula to size VOL capacity of external storage

If you use an external volume, calculate the total capacity of parity groups that are associated with

the CLPR.

Formula to size VOL capacity of Thin Provisioning or Smart Tiers

If you use a virtual volume, calculate the total LDEV capacity of the virtual volume that is associated

with the CLPR.

To check the LDEV capacity of the virtual volume, see the LDEVs tab in the Logical Devices window

of Remote Web Console.

Cache capacity with Thin Provisioning or Smart Tiers

You have to allocate more cache capacity for each CLPR when Thin Provisioning or Smart Tiers

or both applications are in use.

Also, use the next table when you enable Cache Mode for External Storage with Thin Provisioning

or Smart Tiers. For the formula to calculate the internal volume capacity for a CLPR, see “Formula

to size VOL capacity of internal storage” (page 9).

Recommended cache capacity for

a CLPR

Number of MP bladesInternal/external VOL for a CLPR (Total capacity)

12 GB2Less than 4 TB

20 GB4

28 GB6

36 GB8

44 GB10

52 GB12

60 GB14

68 GB16

16 GB24 TB or more