Mylex AcceleRAID 352, Installation Manual

Page: 42 / 92

BBM Operation
A-2 AcceleRAID 352 Installation Guide
BBM Operation
This BBM consists of a Lithium-Ion battery, a charging circuit, and power
monitoring circuitry. The controller is shipped with an optional BBM
installed or with standard DIMM memory (without a BBM).
Set-up – Enabling the Write-Back Cache
Maximum RAID performance is achieved when the cache is in write-back
mode. The write-back cache is enabled by toggling the write-back/write-
through mode switch. The write-back/write-through mode switch is accessed
using RAID EzAssist (the BIOS Configuration Utility) or in GAM. Refer to
the
RAID EzAssist Configuration Utility User Reference Guide or the Global
Array Manager Client Software Installation Guide and User Manual for
instructions on how to examine and change the mode switch.
Battery Backup Capacity
The battery backup’s capacity varies with the cache memory capacity used.
In the event of a power failure, the battery backup can be expected to
maintain cache data integrity for the periods of time shown in Table A-1. For
more information about battery duration, please see “Battery Charge Life
(Data Retention)” later in this chapter.
Table A-1. Typical Battery Backup Capacity
Memory Size Approximate Battery Charge Life
32MB 168 hours
64MB 110 hours
128MB 60 hours