HP XP7 Storage - Manual (Page 10)

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 blades Internal/external VOL for a CLPR (Total capacity)
12 GB 2 Less than 4 TB
20 GB 4
28 GB 6
36 GB 8
44 GB 10
52 GB 12
60 GB 14
68 GB 16
16 GB 2 4 TB or more
20 GB 4
28 GB 6
36 GB 8
44 GB 10
52 GB 12
60 GB 14
68 GB 16
24 GB 2 16 TB or more
24 GB 4
10 Cache Partition operations