Sounds like a problem with at least one of the drives. With a RAID system, some data may be saved, but best get an expert to try and recover it for you. RAID (redundant array of independent disks) was used to improve performance by spreading data across two or more drives, and to provide a level of redundancy for failures. If you are set up for RAID 1 Mirroring, then all data has a full backup, and you are in good shape. With just two drives, everything may be recovered, but like I said, you probably need help.
raid Mirrowing,
