Should a backup server use RAID?

Solution 1:

Imo, there's a massive benefit to using raid.

If the backup machine has a disk failure without raid then you'll lose all your backups. How long will it take you to rebuild them?

Also, what if you lose all your backups due to a disk failure, successfully rebuild them, and then need to find something that was backed up previously but got lost cause of this disk failure.

If nothing else, disks are now so cheap that the cost of an extra disk to put the system in raid 5 will probably cost less than your time in the event you needed to recover from a failure.

Solution 2:

Server computers should have redundant disks except in very special circumstances (think rack after rack of "scale out" 1U application servers, like Google). A server computer w/o redundant disks is a ticking time bomb.

That having been said, backup isn't backup unless it's off site and offline. If it's on-site but offline (tapes in a drawer) then it's gone when the building burns down (see Cleaning soot out of a server ). If it's off-site but online then it's vulnerable to attack and "corruption".

And now, stay tuned for religious arguments about disk versus tape, etc.