Technical data

2–18 HSG80 ACS Solution Software Version 8.6 for Compaq Tru64 UNIX Installation and Configuration Guide
■ A mirrorset should only contain disk drives of the same capacity.
■ Spread mirrorset members across different device ports (drive bays).
■ 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 percent 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 2–14 shows an
example of a RAIDset that uses five members.
Figure 2–14. A 5-member RAIDset using parity
Virtual disk
Block 0
Block 1
Block 2
Block 3
Block 4
Block 5
etc.
Disk 1
Block 0
Block 5
Block 10
Block 15
Disk2
Block 1
Block 6
Block 11
Parity 12-15
Disk 3
Block 2
Block 7
Parity 8-11
Block 12
Disk 4
Block 3
Parity 4-7
Block 8
Block 13
Disk 5
Parity 0-3
Block 4
Block 9
Block 14
Operating
system
view
RAIDset
CXO6463B