HP StorageWorks 3000 RAID Array - Manual (Page 54)

2-12 RAID Array 3000 Controller Shelf Hardware User’s Guide
Compaq Confidential – Need to Know Required
Writer: Bob Young Project: RAID Array 3000 Controller Shelf Hardware User’s Guide Comments:
Part Number: EK-SMCPQ-UG. D01 File Name: c-ch2 RAID Array 3000 Controller.doc Last Saved On: 12/4/00 1:08 PM
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.
1110
1101
1011
Host Data
Controller divides
the data into
chunksized units
1110
1101
1011
Striped data written
to half the drives
Striped data mirrored
to the remaining drives
SHR-1056
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.