Raid 0+1; Figure 2-7. Diagram Of Raid 0+1 Write - Compaq StorageWorks RAID Array 3000 Controller Shelf User Manual

2-12 RAID Array 3000 Controller Shelf Hardware User's Guide

RAID 0+1

RAID 0+1 (see Figure 2– 7) combines RAID 0 (striping) with RAID 1
(mirroring). In RAID 0+1 write, the controller breaks up the data block from
the host into smaller chunks, then writes the chunks to half the drives in the
array, while writing duplicate chunks to the remaining drives.
Controller divides
Host Data
the data into
chunksized units
1110
1101
1011

Figure 2-7. Diagram of RAID 0+1 write

In the event of a drive failure, a RAID 0+1 array will enter degraded mode and
continue to operate by substituting the failed drive with its mirror.
Striped data written
to half the drives
1110
1101
Striped data mirrored
1011
to the remaining drives
SHR-1056