Users Guide

In addition, the Patrol Read operation suspends during heavy I/O activity and resumes when the I/O is
complete.
NOTE: For more information on how often the Patrol Read operation runs when in auto mode, see
the respective controller documentation.
Load Balance
The Load Balance property provides the ability to automatically use both controller ports or connectors
connected to the same enclosure to route I/O requests. This property is available only on SAS controllers.
BGI Rate
On PERC controllers, background initialization of a redundant virtual disk begins automatically within 0 to
5 minutes after the virtual disk is created. The background initialization of a redundant virtual disk
prepares the virtual disk to maintain redundant data and improves write performance. For example, after
the background initialization of a RAID 5 virtual disk completes, the parity information has been initialized.
After the background initialization of a RAID 1 virtual disk completes, the physical disks are mirrored.
The background initialization process helps the controller identify and correct problems that may occur
with the redundant data at a later time. In this regard, the background initialization process is similar to a
check consistency. The background initialization should be allowed to run to completion. If cancelled,
the background initialization automatically restarts within 0 to 5 minutes. Some processes such as read
and write operations are possible while the background initialization is running. Other processes, such as
creating a virtual disk, cannot be run concurrently with a background initialization. These processes cause
the background initialization to cancel.
The background initialization rate, configurable between 0% and 100%, represents the percentage of the
system resources dedicated to running the background initialization task. At 0%, the background
initialization has the lowest priority for the controller, takes the most time to complete, and is the setting
with the least impact to system performance. A background initialization rate of 0% does not mean that
the background initialization is stopped or paused. At 100%, the background initialization is the highest
priority for the controller. The background initialization time is minimized and is the setting with the most
impact to system performance.
Check Consistency
The Check Consistency task verifies the accuracy of the redundant (parity) information. This task only
applies to redundant virtual disks. When necessary, the Check Consistency task rebuilds the redundant
data. If the virtual disk is in a Failed Redundancy state, running a check consistency may be able to return
the virtual disk to a Ready state.
The check consistency rate, configurable between 0% and 100%, represents the percentage of the
system resources dedicated to running the check consistency task. At 0%, the check consistency has the
lowest priority for the controller, takes the most time to complete, and is the setting with the least impact
to system performance. A check consistency rate of 0% does not mean that the check consistency is
stopped or paused. At 100%, the check consistency is the highest priority for the controller. The check
consistency time is minimized and is the setting with the most impact to system performance.
Create or Change Security Keys
When configuring the controller properties, you can create or change the security keys. The controller
uses the encryption key to lock or unlock access to SED. You can create only one encryption key for
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