3PAR InForm® OS 2.3.1 Concepts Guide (320-200112 Rev B, February 2010)

8.5
RAID Types
InForm OS Version 2.3.1 3PAR InForm OS Concepts Guide
Figure 8-2 shows a RAID 10 logical disk with a set size of 2 and a row size of 3 in two rows:
Figure 8-2. Data Striped Across RAID 1 Sets on a RAID 10 Logical Disk
8.4.3 RAID 5 and 50
On a RAID 50 logical disk, data is striped across rows of RAID 5 sets. A RAID 5 set, or parity set,
must contain at least three chunklets. A RAID 5 set with three chunklets has a total of two
chunklets of space for data and one chunklet of space for parity. RAID 5 set sizes with between
3 and 9 chunklets are supported. The data and parity steps are striped across each chunklet in
the set. The chunklets in each RAID 5 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 50 logical disk in step sizes.
The step size is the number of contiguous bytes that the system accesses before moving on to
the next chunklet. A RAID 5 set can function with the loss of any one of the chunklets in the
set.
A
D
n-3
Set size*
Step size
Row size
= Chunklet
RAID 10 Logical Disk
*Mirror depth
A‘
D‘
n-3‘
B
E
n-2
B‘
E‘
n-2‘
C
F
n-1
C‘
F‘
n-1‘
n
n+3
n‘
n+3‘
n+1
n+4
n+1‘
n+4‘
n+2
n+5
n+2‘
n+5‘
Row 1
Row 2