3ware RAID BBU(Backup Battery Unit)

BBU가 있으면 72시간 까지는 갑작스런 정전으로 전기가 나가도
저장하려던 내용을 유지할수 있고, 전원이 복구되면 저장을 한다는데

어짜피 RAID 정도 쓰는데라면
UPS를 쓸텐데 어떻게 보면 이런 BBU를 왜 장착해 놓나 싶기도 하고..

Appendix A. Installing  the Battery Backup Unit The Battery Backup Unit (BBU) is an add-on that can be attached to a 3ware 9000 RAID controller to supply power to the memory module from an attached battery pack in the event of a system power loss. This allows the controller to use write-caching for optimal performance and not be exposed to data loss in the event of a system power failure. When fully charged, the battery preserves the contents of the controller cache memory for a limited period of time (up to 72 hours). When power is restored, cached data is flushed to disks.