You haven't said how your drives are set up. If they are RAID1 then it should be safe to allow the format, RAID 0 then you have big problems. For single disks test on your computer.
A simple test, take out the drive and put it in a USB /SATA caddy and see if you can read it with your computer. If you are running windows an easy way of doing this is to get a live CD Linux distro and boot from that.
If you can read the drive and have space on another drive copy the files there, put the drive back in the 323, format it and copy the files back.
The problem with the drive may be something simple or it could be that the drive is on the way out.