Hardware RAID Controller and Disk Write Caches

It is important that all hard disk drives obey the "flush" command and write their caches before the command completes. Unfortunately, not all hardware RAID controllers and drives do this, which may lead to data inconsistencies and file system corruptions on a power failure.

Some 3ware RAID controllers do not disable disk write caches and do not send "flush" commands to disk drives. As a result, the file system may sometimes become corrupted even though the RAID controller itself has a battery. To solve this problem, disable writes caches on all disk drives in the RAID.

Also, make sure that your configuration is thoroughly tested for consistency before deploying a Parallels Cloud Storage cluster. For information on how you can do this, see SSD Drives Ignore Disk Flushes .