HP StorageWorks HSG80 ACS Solution Software V8.8 for HP-UX Installation and Configuration Guide (AA-RV1FA-TE, March 2005)

Planning Storage Configurations
88 HSG80 ACS Solution Software V8.8 for HP-UX Installation and Configuration Guide
■ A RAIDset must include at least 3 disk drives, but no more than 14.
■ A storageset should only contain disk drives of the same capacity. The
controller limits the capacity of each member to the capacity of the smallest
member in the storageset. Thus, if you combine 9 GB disk drives with 4 GB
disk drives in the same storageset, you waste 5 GB of capacity on each 9 GB
member.
■ RAIDsets are particularly well-suited for the following:
— Small to medium I/O requests
— Applications requiring high availability
— High read request rates
— Inquiry-type transaction processing
■ RAIDsets are not particularly well-suited for the following:
— Write-intensive applications
— Database applications in which fields are continually updated
— Transaction processing
Striped Mirrorset Planning Considerations
Striped mirrorsets (RAID 0+1) are a configuration of stripesets whose members
are also mirrorsets (Figure 29). Consequently, this kind of storageset combines
the performance of striping with the reliability of mirroring. The result is a
storageset with very high I/O performance and high data availability. Figure 30
shows a second example of a striped mirrorset using six members.