Raid Multi-Parity - HP 3PAR StoreServ 7200 2-node Manual

Figure 5 Data Striped Across RAID 5 Sets on a RAID 50 Logical Disk

RAID Multi-Parity

On a RAID Multi-Parity (MP) or RAID 6 logical disk, data is striped across rows of RAID MP sets.
A RAID MP set, or double-parity set, must contain at least 8 chunklets. A RAID MP set with 8
chunklets has a total of 6 chunklets of space for data and 2 chunklets of space for parity. RAID
MP set sizes of 8 and 16 chunklets are supported. The data and parity steps are striped across
each chunklet in the set. The chunklets in each RAID MP set are distributed across different physical
disks, which may be located in different drive magazines or even different drive cages. The number
of sets in a row is the row size. The system accesses the data from a RAID MP logical disk in step
sizes. The step size varies and is dependent on the size of the RAID MP set. A RAID MP set can
function with the loss of any two of the chunklets in the set.
The following example shows 2 RAID MP sets in one row, the second set is shown below the first
set. In the first RAID MP set in the following example, p0 is the parity step for data steps F, L, M,
Q, T, V, and X. Figure 6 (page 38) shows a RAID MP logical disk with a set size of 8, and 2 sets
in 1 row:
RAID Types 37