Hitachi Universal Storage Platform VM - Manual (Page 42)

2-16 Architecture and Components
Hitachi Universal Storage Platform V/VM User and Reference Guide
Intermix Configurations
RAID-Level Intermix
RAID technology provides full fault-tolerance capability for the data drives of
the Universal Storage Platform V/VM. The cache management algorithms
enable the USP V/VM to stage up to one full RAID stripe of data into cache
ahead of the current access to allow subsequent access to be satisfied from
cache at host channel transfer speeds.
The Universal Storage Platform V/VM supports RAID-1+0 (RAID-10), RAID-5,
RAID-6, and intermixed RAID-level configurations, including intermixed array
groups within an array domain.
Figure 2-8 illustrates an intermix of RAID
levels. All types of array groups (RAID-5 3D+1P, 7D+1P; RAID-10 2D+2D,
4D+4D; RAID-6 6D+2P) can be intermixed under one BED pair.
03
46 47 02 03
46 47 02 03
46 47
46 47
BED
(CL1)
RAID group
(7D+1P/6D+2P)
BED
(CL2)
0
1
2
3
0
1
2
3
1st, 3rd
5th or 7th
BED Pair
RAID group
(2D+2D)
02
02
03
46 47 02 03
46 47 02 03
03 46 47 02
BED
(CL2)
0
1
2
3
BED
(CL1) 0
1
2
3
46 47 02 03
RAID group
(4D+4D)
RAID group
(3D+1P)
RAID group
(3D+1P)
2nd, 4th
6th or 8th
BED Pair
01
00 01
00 01
01 00
01 00
00 01
00 01
00
00 01
RAID group
(4D+4D)
Figure 2-8 Sample RAID Level Intermix