I once worked with a customer that had a finite number of tapes that they used for their database backups:crazy:. Their database was big enough to have to use slightly more than one tape for each backup. So, when the time came to actually have to restore the database (due to a bad disk causing corruption), they discovered that the only complete backup set was the latest, and it too had the corrupted data on it. They wanted me to "recover as much as you can from an earlier backup", which of course was impossible because parts of the backup had been overwritten by a later backup. Needless to say, they came up with a better strategy AFTER that.