HP XP P9500 Storage - Manual (Page 7)

(iv) When Compatible XRC is used:
When you use Compatible XRC for a CLPR, cache capacity for administrative information called
sidefile is needed. Therefore, you may want to add larger cache capacity than the recommended
cache capacity calculated from (i), (ii), or (iii) with sleep wait threshold in mind.
Calculate the recommended capacity using the formula below:
Recommended cache capacity = (Recommended cache capacity calculated from (i)-(iii)) × 100 /
(100 - (Sleep wait threshold))
(v) When only External Storage is used:
If the CLPR to be created meets the following conditions, the recommended cache memory capacity
in the table below can be applied.
•
The CLPR uses only external volumes.
•
The transfer speed is not emphasized.
•
The cache mode of the mapped volume is Disable.
•
The CLPR uses only volumes that are for Open systems.
Recommended cache capacity for a
CLPR Number of processor
blades Total capacity of external volume of CLPR in which
only Ext Stor is used
4 GB 2 or 4 Less than 128,000
8 GB 6 or 8
8 GB 2 or 4 128,000 or more
16 GB 6 or 8
When adding cache memory, use either the Standard Cache Access Model mode or the High
Performance Cache Access Model mode. If your storage system has any additional printed circuit
boards (PCBs), you must use the High Performance Cache Access Model mode. For more information
about adding cache memory, contact the HP Technical Support.
Cache partitioning rules and guidelines
Observe the following rules, restrictions, and guidelines when creating cache logical partitions:
For the priority mode cache requirements, see the HP XP P9000 Performance for Open and
Mainframe Systems User Guide.
You can operate Cache Partition from Remote Web Console or RAID Manager. To use RAID
Manager, see the HP XP P9000 RAID Manager User Guide.
Rules
•
Cache Partition must be enabled on your system.
•
CLPR0 is the default CLPR in a storage system. If you have not yet created any cache logical
partitions, all cache belongs to CLPR0.
•
Usually, you can create a CLPR if the storage system has 4 GB cache. However, when creating
a CLPR while using Cache Residency, the remaining cache size, which is calculated by
subtracting Cache Residency size from the cache size of CLPR0, must be 8 GB or more.
•
Adding or changing CLPR definitions or configurations may take hours to implement and
cannot be canceled or modified until all changes are complete. For assistance or for more
information, contact your HP account team.
Cache partitioning rules and guidelines 7