Glossary

controller task. Selecting this option clears the redundant path view and the connectors are represented
on the user interface as Connector 0 and Connector 1.
Related Links
Setting The Redundant Path Configuration
Logical Connector Properties And Tasks
Setting The Patrol Read Mode
NOTE: This task is not supported on PERC hardware controllers running in HBAmode.
Does my controller support this feature? See Supported Features.
Patrol read identifies disk errors in order to avoid disk failures and data loss or corruption. The Set Patrol
Read task is applicable only for disks used as virtual disks or hot spares.
The Set Patrol Read task runs in the background and corrects, when possible. When the Set Patrol Read
mode is set to Auto, patrol read is initiated when the controller is idle for a period of time and when no
other background tasks are active. In this scenario, the patrol read enhances the system performance as
disk errors can be identified and corrected when there is not input/output activity on the disk.
The controller adjusts the amount of system resources dedicated for patrol read based on the amount of
controller activity that is competing with the Patrol Read task. When the controller activity is high, fewer
system resources are dedicated to the patrol read task.
Patrol Read does not run on a physical disk in the following circumstances:
• The physical disk is not included in a virtual disk or is assigned as a hot spare.
• The physical disk is included in a virtual disk that is currently undergoing one of the following:
– Rebuild
– Reconfiguration or reconstruction
– Background initialization
– Check consistency
In addition, the Patrol Read suspends during heavy I/O activity and resumes when the I/O is finished.
Related Links
Starting And Stopping Patrol Read
To Set The Patrol Read Mode
Select the desired Patrol Read Mode option. The options available are:
• Auto — Initiates the Patrol Read task. After the task is complete, it automatically runs again within a
specified period. For example, on some controllers the Patrol Read runs every four hours and on
other controllers, the Patrol Read runs every seven days. The Patrol Read task runs continuously on
the system starting again within the specified period after each iteration of the task completes. If the
system reboots while the Patrol Read task is running in Auto mode, the Patrol Read restarts at zero
percent (0%). When the Patrol Read task is set to Auto mode, you cannot start or stop the task. Auto
mode is the default setting.
NOTE: For more information on how often the Patrol Read task runs when in Auto mode, see
your controller documentation.
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