Users Guide

You must have Login and Server Control privilege to configure the controller properties.
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 undergoing one of the following:
– A rebuild
– A reconfiguration 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.
NOTE: Patrol read mode operations such as Start and Stop are not supported if there are no virtual
disks available in the controller. Though you can invoke the operations successfully using the iDRAC
interfaces, the operations fail when the associated job is started.
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 later. 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.
239