HSG80 ACS Solution Software Version 8.7 for Compaq Tru64 UNIX Installation and Configuration Guide

Table Of Contents
Planning Storage Configurations
2–21HSG80 ACS Solution Software Version 8.7 for Compaq Tru64 UNIX Installation and
Configuration Guide
2–21
Mirrorset Planning Considerations
Mirrorsets (RAID 1) use redundancy to ensure availability, as illustrated in Figure
2–7. For each primary disk drive, there is at least one mirror disk drive. Thus, if a
primary disk drive fails, its mirror drive immediately provides an exact copy of the
data. Figure 2–8 shows a second example of a Mirrorset.
Figure 2–7: Mirrorsets maintain two copies of the same data
Figure 2–8: Mirrorset example 2
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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.