Tails of The Unexpected - Why Does RAID Fail?

RAID is probably one of the first things that a well seasoned system administrator or IT service provider will start configuring on a newly installed server, prior to setting up the OS.

By implementing RAID as part of a backup strategy you would be forgiven if you though that your data could then be classed as safe. Even when RAID is used it should be part of a well rounded backup solution, if it isn't and the RAID system fails, you might find yourself ask your self where did it all go wrong?

RAID isn't bullet proof

RAID 5 is fault tolerant to one disk so if for example you have 3 disks in your server and one fails it will still keep on trucking, however if two disks fails you'll find that the RAID will come to a screeching halt. RAID 6 on the other hand is fault tolerant to 2 disks, so on the same 3 disk set-up you'll not hit trouble until two out of the three disks fail.

So what are the odds of more than one or two of the disk failing at the same time? Slim right? Well unfortunately multiple disk failures can happen more often that you would like to think, one reason for this is that the majority of the time identical hard disk drives are used, this means that the chances that the drives fail simultaneously increases significantly, this is especially true if the drives have a common fault or firmware bug as seen in some recent Seagate models. There is also the chance that all the hard drive fail due to a power supply becoming faulty and frying the hard disks in one fell swoop.

The other common cause if RAID failure is that one disk goes down and simply isn't changed and then later down the line another one falls over causing the RAID to then fail.

Other causes of failure typically are:-

RAID controller failure.

Raid rebuild failure

Corrupted RAID configuration

Incorrect replacement of a working disk instead of the original faulty drive.

Physical damage due to fire, flood or earthquake.

What to do if you RAID fails

If you are in the unfortunate position to require RAID data recovery why not contact one of cleardata's friendly customer representatives on 0800 046 8087 to learn how we can help with your RAID 6 or RAID 5 data recovery issues.