Technical data

Planning Storage 2–17
Figure 2–12. Mirrorsets maintain two copies of the same data
Figure 2–13. Mirrorset example 2
Keep these points in mind when planning mirrorsets:
■ Data availability with a mirrorset is excellent but comes with a higher cost—you need
twice as many disk drives to satisfy a given capacity requirement. If availability is your
top priority, consider using dual-redundant controllers and redundant power supplies.
■ You can configure up to 20 mirrorsets per controller or pair of dual-redundant
controllers. Each mirrorset may contain up to 6 members.
■ Both write-back cache modules must be the same size.
D
i
s
k
1
0
0
0
0
D
i
s
k
2
0
1
0
0
D
i
s
k
1
0
2
0
0
D
i
s
k
2
0
0
0
0
D
i
s
k
1
0
1
0
0
D
i
s
k
2
0
2
0
0
CXO7288A
A'A
B'
B
C'C
Mirror drives contain
copy of data
Operating
system
view
Actual
device
mappings
Mirrorset
CXO4594B
Disk 1
Block 0
Block 1
Block 2
etc.
Disk 2
Block 0
Block 1
Block 2
etc.
Virtual disk
Block 0
Block 1
Block 2
etc.