A disk failure on a drive that houses database files is a reality that some database administrators must deal with. This situation can give pause to the most seasoned administrators, but it is a situation that can be addressed with little or no data loss. Don’t panic! You need to first identify the available backups.
Hopefully, the disk that experienced a failure is not the same disk that houses your backups. Database backups should always be stored on separate media. One of the best approaches is to write the backups to a drive that does not contain any other SQL Server files and write the contents of that drive to tape. This minimizes the possibility of losing one of those all-important backups.