Step 9 Order Flash-Backed Write Cache (Optional) - Cisco UCS B420 M3 Manual

CONFIGURING the SERVER
STEP 9 ORDER FLASH-BACKED WRITE CACHE (OPTIONAL)
You may order an optional 1 GB flash-backed write cache, which backs up the data written to
the RAID controller write cache in the event of a power failure. The flash-backed write cache
consists of a 1 GB memory module and a supercapacitor power backup module that connects to
the motherboard with a cable. The ordering information is shown in Table 14.
Table 14 Flash-backed Write Cache
Product ID (PID) PID Description
UCSB-FBWC-1GB Flash-backed write cache for LSI 2208R RAID controller
The flash-backed write cache provides RAID controller cache protection using NAND flash
memory and a supercapacitor. In the event of a power or server failure, cached data is
automatically transferred from the RAID controller DRAM write cache to flash. Once power is
restored, the data in the NAND flash is copied back into the DRAM write cache until it can be
flushed to the disk drives.
For the location of the supercap and the 1 GB memory module, see Figure 5 on page 35.
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