3PAR InForm® OS 2.2.4 Concepts Guide (320-200085 Rev B, March 2009)

2.5
3PAR Storage Concepts and Terminology
InForm OS Version 2.2.4 3PAR InForm OS Concepts Guide
Figure 2-2 shows a RAID 10 logical disk with a set size of 2 and a row size of 3 in two rows:
Figure 2-2. Data is Striped Across RAID 1 Sets on a RAID 10 Logical Disk
2.1.2.1.3 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: two for data and one for parity. The chunklets in each
RAID 5 set are on different physical disks, which may also be on 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. A step size is the number of contiguous bytes
that the system accesses before moving on to the next chunklet.
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