RAIDWatch User's Manual

RAIDWatch User’s Manual
7.3 Controller
“Controller” here refers to the RAID controller unit, which is the main
processing unit of a RAID subsystem. The configuration window contains
two sub-windows: “Caching” and “Controller Parameters.” To configure the
controller’s caching behaviors, select an appropriate value from each of the
pull-down menus, as shown in Figure 7-3.
Figure 7-3: The Controller Page
The data cache can be configured for optimal I/O performance using the
following variables:
Caching Parameters
♦ Write-Back Cache
• Enabled, Host Writes are cached before being distributed to
hard drives. This improves write performance but requires
battery backup support to protect data integrity in case of a
power outage.
• Disabled, Cache Write-Through. Used primarily if no cache
battery backup is installed and if there is increased likelihood of
a power failure.
♦ Optimization Policy
• Optimization for Random I/O. More common setting. Use this
option for environments (e.g., database maintenance) with
smaller I/O transactions.
7-4 Controller