HP Configuring Arrays Reference Manual page 9

To support some controller features, the controller may also require a hardware configuration that includes
the following cache (array accelerator) options:
•
A cache module that is 256 MiB or larger
•
A compatible battery pack or capacitor pack
To obtain these options, contact an HP authorized reseller or see the HP website
(http://www.hp.com/products/smartarray).
HP Smart Array Advanced Pack 9