Raid 1/0 Group (Mirrored Raid 0 Group) - EMC CX700 Planning Manual

RAID Types and Trade-offs
Figure 2-4

RAID 1/0 Group (Mirrored RAID 0 Group)

2-8 EMC CLARiiON CX300, CX500, CX500i, and CX700 Storage Systems Configuration Planning Guide
With a RAID 1 mirrored pair, the storage system writes the same data
to both disks, as follows.
0 1
Second Disk
0
1
RAID 1 Mirrored Pair
A RAID 1/0 Group consists of four, six, eight, ten, twelve, fourteen,
or sixteen disks. These disks make up two mirror images, with each
image including two to eight disks. The hardware automatically
mirrors the disks. A RAID 1/0 Group uses disk striping. It combines
the speed advantage of RAID 0 (Page 2-10) with the redundancy
advantage of mirroring. With a RAID 1/0 Group, you can create up
to 128 RAID 1/0 LUNs to apportion disk space to different users,
servers, and applications.
Figure 2-5 shows the distribution of user data with the default stripe
element size of 128 sectors (65,536 bytes) in a six-disk RAID 1/0
Group. Notice that the disk block addresses in the stripe proceed
sequentially from the first mirrored disks (first and fourth disks) to
the second mirrored disks (second and fifth disks), to the third
mirrored disks (third and sixth disks), and then from the first
mirrored disks, and so on.
First Disk
2 3 4
3
2 4
...
User Data
...
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