Array Configuration Utility User Guide

Using the Command Line Interface 52
where <target> is a logical drive.
The following limitations apply to this command:
• You cannot simultaneously query the RAID level and the stripe size of any given logical drive.
• If you do not specify a RAID level for a query or migration, the CLI uses the existing value by default.
• If you do not specify a stripe size, the CLI uses the default stripe size value for the RAID level that you
specify.
Example commands:
=> ctrl slot=3 ld 1 modify raid=1
=> ctrl slot=4 ld 2 modify ss=16
=> ctrl slot=2 ld 3 modify raid=5 ss=16
Changing the Rebuild Priority setting
The Rebuild Priority setting determines the urgency with which the controller treats an internal command to
rebuild a failed logical drive.
• At the low setting, normal system operations take priority over a rebuild.
• At the medium setting, rebuilding occurs for half of the time, and normal system operations occur for
the rest of the time.
• At the high setting, the rebuild takes precedence over all other system operations.
If the logical drive is part of an array that has an online spare, rebuilding begins automatically when
drive failure occurs. If the array does not have an online spare, rebuilding begins when the failed
physical drive is replaced.
Syntax:
<target> modify rp=high|medium|low
where <target> is a controller.
Example command:
=> ctrl slot=3 modify rp=high
Changing the Expand Priority setting
The Expand Priority setting determines the urgency with which the controller treats an internal command to
expand an array.
• At the low setting level, normal system operations take priority over an array expansion.
• At the medium setting, expansion occurs for half of the time, and normal system operations occur for
the rest of the time.
• At the high setting, the expansion takes precedence over all other system operations.
Syntax:
<target> modify ep=high|medium|low
where <target> is a controller.
Example command:
=> ctrl slot=3 modify ep=high
Changing the controller cache ratio
The controller cache ratio setting determines the amount of memory allocated to read and write
operations. Different types of applications have different optimum settings. You can change the ratio only