User`s guide

3.3.3 Optimal Performance Configurations
For optimal performance, configure to the following guidelines:
• Balance the number of devices on each port of the controller. For example, for
18 (35) SBBs attach three devices on each of the six ports. This maximizes
parallel activity across the controller’s available ports. Figure 3–10 is an
example of how to balance devices across ports.
• Intermixing higher and lower performance devices on each port is beneficial.
Therefore, put higher performance devices on separate ports. For example,
put multiple solid state disks on separate ports.
Use the guidelines given in Table 3–1.
Table 3–1 High-Performance Devices per Port
Number of Relatively
Higher Performance
Devices
Maximum Number of
Devices
Configured per Port:
6-Ported
Maximum Number of
Devices
Configured per Port:
3-Ported
1-3 1 1
4-6 1 2
7-9 2 3
10-12 2 4
13-15 3 5
16-18 3 6
• Maximize the amount of cache memory per controller with the 16- or 32-MB
cache module option.
Highest Performance
Use a dual-redundant controller configuration and balance the number of devices
across the two controllers. Do this through your operating system by ordering
how the devices are mounted or sequenced, or through the controller by setting
preferred path definitions.
This results in approximately half of the devices normally accessed through each
controller. Should one controller fail, its devices fail over to the other controller
automatically.
3–14 Configuration Rules and Restrictions