Wait, case may not be closed...
You say you configured the RAID to work as a backup. There is no RAID configuration that can possibly be used as a backup. So I am hoping you are not relaying on a mirrored RAID set as a backup.
The reason a mirrored RAID is not a backup, is because no data is ever retained when a file is changed or deleted. That is, the process of making a change to a file, or deleting a file is replicated on all drives that make up the RAID set. If you accidently delete your checkbook data, it's gone, you can't get it back from your RAID set. If you need to look at files to see what you were doing two months ago, and you have made changes to those files since then, poof, it is gone, no way to return to that data.
Mirrored RAID is not a backup. It's main purpose is to provide redundancy of hardware to insure that if a drive should fail that you can continue to operate with all data intact, as you make any needed hardware repairs or replacements. Mirrored RAIDS are to hep insure the maximum amount of uptime on your data storage system.
So if your intent was to use a mirrored RAID array for backup, please reconsider. If you were instead using the mirrored array as it was intended, please forgive my slight rant about what mirrored RAIDs are for.
Thanks,
Tom N.