Array Accelerator - Compaq ProLiant 5000 Reference Manual

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9-4 Compaq SMART-2 SCSI Array Controller

Array Accelerator

An Array Accelerator is available on the SMART-2 Controller to improve
performance on data access to the drive array. The write cache can accept
data from the server at the maximum PCI or EISA burst rate while writing to
the array at the time and rate the drives can accommodate. The read cache
accepts data from the array and acts as a buffer to transfer the data to the
server at higher data rates. The Array Accelerator feature may be disabled by
software
if desired.
The Array Accelerator write and read cache is made up of ECC (Error
Checking and Correcting) memory, providing a high level of data integrity
without mirroring. ECC memory can detect and correct some hard and soft
memory errors without affecting performance.
The write cache memory is backed up with onboard rechargeable batteries,
insuring that the data temporarily held (cached) there is safe even with
equipment failure or power outage. The batteries will preserve data in the
write cache for up to four days.
IMPORTANT:
discharged when the board is first installed. During server power up with
discharged Array Accelerator batteries, POST (Power On Self Test) will display the
code "1794," indicating that the Array Accelerator is disabled. This is not a problem
that requires action on your part. The Array Accelerator will automatically be
enabled when the batteries are charged to 90% of their capacity.
It may take up to 36 hours for the internal circuitry to charge the batteries fully.
During this time the Array Accelerator will be disabled but the SMART-2 Controller
will function properly, although without the performance advantage of the
Array Accelerator.
Writer: Project: Compaq SMART-2 SCSI Array Controller Comments:
The rechargeable batteries on a new SMART-2 Controller may be
File Name: M-ch9.doc Last Saved On: 4/22/97 1:01 PM