I read on one of the the postgres mailing list a while back that battery backup makes a huge difference on the LSI SCSI RAID cards, and I know that at least some of the Areca cards takes a battery. The other thing that I picked up there was that non-SCSI disks routinely lie about when data being committed to disks (opposed to just written to cache). Cheap disks hence appear faster than they are, and your data may not actually by sync'ed as expected. No idea if that is the case of SATA drives, or how to tell if a particular drive does the "right" thing. Hardware raid cards use a proprietary format on your disks. Should your controller die, you better have a replacement handy, able to buy one or be prepared to restore your data from backup. Not sure if this is the case for non-RAID controllers (I think some SCSI cards play this trick as well). Whatever route you go, if you cannot monitor your array it buys you no safety. /Allan
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