HSG80 ACS Solution Software V8.6 for Windows NT and Windows 2000 Installation and Configuration Guide

2–18 HSG80 ACS Solution Software Version 8.6 for Windows NT and Windows 2000 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