wrote:
On several occasions I have seen situations where faulty UPS's caused
servers wtih RAID 5 arrays to reboot continuosly which caused
corruption to either the RAID array itself or the file system. I am
considering recommending RAID1 whenever possible because I suspect
that it would be more resillient under the same conditions because I
have two seperate copies of the system and I do not suspect that
mirroring would mirror NTFS corruption or suffer from the problems of
RAID 5 array corruption. I would like to hear your opinions on this.

thanks

hardware mirroring will copy any garbage you throw at it, so if your
operating system fails to complete a write, and the RAID array is still
working, it will write what it gets.

Luckily, NTFS is pretty tough and fairly hard to corrupt, as well as it
comes up ok from unclean shutdowns pretty well.

If the underlying RAID itself is corrupted from a dirty shutdown, yes,
your NTFS may break, and the array may detect itself as degraded or
failed and may not even let you access it.

Not having a junk UPS is best, but if you're going to have to deal with
this, I'd suggest sticking with raid1. It's far simpler, and faster. If
everything goes to hell, you can usually just run off one disk. Raid5 will
limp along with bad disk, bad being either really failed, or just marked
bad by the raid controller.

A battery backed cache on your raid controller may help too. It can save
writes that never happed for commit to disks after power is restored.