Users Guide

Patrol Read Mode Considerations
Patrol read identifies disk errors to avoid disk failures, data loss, or corruption.
The Patrol Read does not run on a physical disk in the following circumstances:
● The physical disk is not included in a virtual disk or assigned as a hot spare.
● The physical disk is included in a virtual disk that is currently undergoing one of the following:
○ A rebuild
○ A re-configuration or reconstruction
○ A background initialization
○ A check consistency
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 each encryption-capable controller. The security
key is managed using the Local Key Management (LKM) feature. LKM is used to generate the key ID and the password or key
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Managing Storage Devices