If you are using only Universal Volume Manager, sometimes you can allocate less cache capacity to a CLPR. To use less cache capacity, the CLPR that you want to create must meet the following conditions:

• The CLPR uses only external open-systems volumes.
• Transfer speed is not important.
• The cache mode of the mapped volume is Disable.

The following table lists the recommended cache capacity for storage systems that use Universal Volume Manager.

Total capacity of external volume of CLPR with UVM	Number of MP units	Recommended cache capacity for a CLPR
Less than 128 TB	4	4 GB
128 TB or more	4	8 GB

When adding cache memory, use either the Standard Cache Access Model mode or the High Performance Cache Access Model mode. If the 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 Hitachi Solution Support Center.