RAID arrays aim to increase the reliability of data storage. Typical configurations tend to allow for either a one or two disk failure without data loss (RAID-5 and RAID-6 respectively).
However, we see a considerable number of RAID arrays sent to us because multiple disks have failed at the same time. On some occasions it has been necessary to recover data from a RAID array when all of the hard disk drives have failed.
In a detailed cast study on the main website we discuss the requirements and methods on how to recover data from a failed RAID array with multiple disk failures in RAID-5 arrays.