RAID 6 arrays consist of at least four drives configured with the data stored in stripes, for example; in an array with 5 drives, each stripe contains 3 data blocks and a two parity blocks. For each stripe, the parity blocks rotate. In the diagram, you can see that in stripe 'A' parity is on disk 3 and 4, on stripe 'B' the parity has rotated to Disk 2 and 3. Hence the term 'Striping with dual rotating parity'

There are also other methods of parity generation and rotation, EMC use standard Row parity and Diagonal Parity. When 2 drives fail in an array, first the missing data using diagonal parity is recalculated, then the row parity for the second failed drive is calculated.

When you send us your RAID equipment for data recovery, we recover the data using our own RAID data recovery software. We can calculate block size, drive order and parity rotation very quickly - no matter how many drives are in the array, and whatever RAID controller is used. Also, our RAID recovery software has built-in bad sector detection and data consistency checking, all performed during hard disk destriping. This means we can rebuild the best possible image from the drives without bad sectors resulting in maximum quality data recovery.