Compaq StorageWorks HSG60 ACS Solution Software V8.6 for Sun Solaris Installation and Configuration Guide

Planning Storage 2–15
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.
A mirrorset should only contain disk drives of the same capacity.
Mirrorsets are well-suited for the following:
Any data for which reliability requirements are extremely high
Data to which high-performance access is required
Applications for which cost is a secondary issue
Mirrorsets are not well-suited for the following applications:
Write-intensive applications (a performance hit of 10% will occur)
Applications for which cost is a primary issue
RAIDset Planning Considerations
RAIDsets (RAID 3/5) are enhanced stripesets—they use striping to increase I/O
performance and distributed-parity data to ensure data availability. Figure 2–11 shows an
example of a RAIDset that uses five members.