Compaq StorageWorks HSG60 ACS Solution Software V8.6 for Compaq Tru64 UNIX 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.