This happened over 10 years ago. I had three drives one with the archives one with the working files and one of the edits (Edits failed me). I had it in double redundancy backup and a on a second NAS. I even at the time copied to DVD. The problem was it happened right away but since my work was in memory it wasn't something I would see till the third day of pulling everything together for the final cut I found out that file system had failed.