Battery Replacement; Alternatives To Battery Replacement; Flash-Backed Write Cache - HP 273914-B21 - Smart Array 6404/256 RAID Controller Technology Brief

The HP 650 mAh P-Series battery has the same form factor as previous versions and extends battery
life up to 48 hours before recharging is necessary.

Battery replacement

HP Smart Array controllers include serviceable battery packs that allow tool-free battery pack
replacement with no need to replace either the Smart Array controller or the detachable cache
module.

Alternatives to battery replacement

If it is not possible or desirable to replace the batteries, administrators have three options to disable
write-back cache and avoid losing critical data:
The ACU provides a method for adjusting the read-and-write cache ratio to 100 percent read
1.
cache.
The ACU provides a method to disable the array accelerator for each logical drive, which disables
2.
both read-ahead and write-back cache.
Administrators can replace an existing RAID controller with a newer Smart Array controller model.
3.
NOTE:
If the write cache is turned off, some write performance degradation may occur.
For more information about Smart Array controller battery configuration and specifications download
the "HP Smart Array Controllers for HP ProLiant Servers User Guide":
http://h20000.www2.hp.com/bc/docs/support/SupportManual/c01608507/c01608507.pdf?ju
mpid=reg_R1002_USEN

Flash-backed write cache

HP introduced the flash-backed write-cache (FBWC) system in the fourth quarter of 2009 (Figure 7).
20