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Dell OpenManage Server Administrator Storage Management User's Guide
RAID Controller Technology: SCSI, SATA, ATA, and SAS
Controller-supported RAID Levels
Controller-supported Stripe Sizes
RAID Controller Read, Write, and Cache Policy
Cluster-enabled RAID Controllers
Creating and Deleting Virtual Disks on Cluster-enabled Controllers
Integrated Mirroring and the PERC 4/IM Controller
Background Initialization on PERC 3/SC, 3/DCL, 3/DC, 3/QC, 4/SC, 4/DC, 4e/DC, 4/Di, 4e/Si, and 4e/Di Controllers
Non-RAID Controller Description
Controller Properties and Tasks
Set Background Initialization Rate
This section describes the controllers supported by Storage Management. Use this section to understand the different controller features.
Most operating systems (OS) do not read and write data directly from the disks, but instead send read and write instructions to a controller. The controller is the hardware in your system that interacts directly with the disks to write and retrieve data. A controller has connectors (channels or ports) which are attached to one or more physical disks or an enclosure containing physical disks. RAID controllers can span the boundaries of the disks so as to create an extended amount of storage space - or a virtual disk - using the capacity of more than one disk.
Controllers also perform other tasks, such as initiating rebuilds, initializing disks, and so on. To complete their tasks, controllers require special software known as firmware and drivers. In order to function properly, the controller must have the minimum required version of the firmware and drivers installed.
Storage Management supports different types of controllers. If your system has a supported controller, the controller is displayed by expanding the Storage object in the tree view. You can select the controller to display tabs for executing controller tasks and viewing controller properties.
Different controllers have different characteristics in the way they read and write data and execute tasks. It is helpful to understand these features to most efficiently manage your storage. The following sections describe the supported controllers and their features.
Storage Management supports RAID controllers using SCSI, SATA, ATA, and SAS technology. This section indicates which technology the supported RAID controllers use. For more information on these controllers, see "Appendix: Supported Features" and the controller hardware documentation.
The following RAID controllers use Small Computer System Interface (SCSI) technology.
The following Cost Effective RAID Controller (CERC) controllers use Serial Advanced Technology Attachment (SATA) technology.
The following Cost Effective RAID Controller (CERC) controllers use Advanced Technology Attachment (ATA) technology.
The following RAID controllers use Serial Attached SCSI (SAS) technology.
Different controllers have different features. If you have more than one controller attached to your system, you may notice that the tasks displayed on the controller's Information/Configuration subtab are different for each controller.
Controllers may also have differences in their read, write, and cache policies as well as how they handle hot spares. You should be aware of these differences when creating virtual disks and assigning hot spares.
The following describes some of the RAID controller features and provides links to a more detailed explanation. For information on which controllers support which features, see "Appendix: Supported Features."
RAID controllers may support different RAID levels. For information on which RAID levels a controller supports, see the supported RAID levels section for the controller in "Appendix: Supported Features."
When creating a virtual disk, you may need to specify the stripe size for the virtual disk. Different controllers have different limitations on the stripe sizes they can support. For information on the stripe sizes a controller supports, see the virtual disk specifications section for the controller in "Appendix: Supported Features."
When creating a virtual disk, you specify the read, write, and cache policies for the virtual disk. The following describes how each of these policies functions.
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NOTE: Read, write, and cache policies are not supported on the CERC SATA1.5/2s controller. |
The read policies indicate whether or not the controller should read sequential sectors of the virtual disk when seeking data.
The write policies specify whether the controller sends a write-request completion signal as soon as the data is in the cache or after it has been written to disk.
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NOTE: Storage Management does not allow you to select the Write-Back policy for controllers that do not have a battery. This restriction protects a controller without a battery from the data loss that may occur in the event of a power failure. On some controllers, the Write-Back policy may be available in the controller BIOS even though it is not available in Storage Management. |
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NOTE: Write-through is the default write policy setting when cluster mode is enabled. In cluster mode, the PERC 3/DC, 4/DC, and 4e/DC controllers only allow write-through caching. |
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NOTE: Storage Management does not allow you to select the Write Cache Enabled Protected policy for controllers that do not have a battery. This restriction protects a controller without a battery from the data loss that may occur in the event of a power failure. When using the Create Virtual Disk Advanced Wizard on a controller without a battery, the wizard will either display Write Cache Disabled as the only available option or the wizard will display no option at all for write policy. |
The Direct I/O and Cache I/O cache policies apply to reads on a specific virtual disk. These settings do not affect the read-ahead policy. The cache policies are as follows:
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NOTE: Cache policy is not supported on any controller that does not have a battery. |
Storage Management supports PERC 3/DC, 4/DC, and 4e/DC controllers that have Microsoft Cluster Server (MSCS) enabled.
A cluster refers to two or more servers that are connected so that their resources can be shared and accessed as if the clustered servers were a single machine. Clusters provide increased availability because when one server in the cluster experiences downtime, another server can take over the processing and workload requests of the failed server.
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NOTE: Storage Management does not set resource ownership in a Microsoft Windows® cluster configuration. |
After a failover of cluster resources, it is necessary to perform a rescan operation in order for Storage Management to display the most up-to-date information about shared resources.
When downloading firmware to a clustered controller, it is recommended that you shut down the other systems in the cluster first. When restarted, the other systems in the cluster should be able to see the firmware updates that you have applied.
If, however, you have downloaded firmware to a controller without first shutting down the other systems in the cluster, you may find that the other systems cannot see the firmware update until you restart the disk management service on those systems. For example, if you download firmware onto system A, and system B cannot see the firmware update, then restart the disk management service on system B.
If you are using a PERC 3/DC, 4/DC, or 4e/DC controller in a cluster configuration, you must shut down and power off the other systems in the cluster before creating or deleting the virtual disk. The following procedure describes the sequence of actions required to create or delete a virtual disk from a cluster-enabled controller. For the purposes of this procedure, the system on which you are creating or deleting the virtual disk is identified as system A and the other system in the cluster is identified as system B.
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NOTE: When creating a virtual disk on a controller that is in a cluster configuration, you must specify the maximum virtual disk size. |
The PERC 4/IM controller enables you to mirror a physical disk that resides internally in the server. This feature can be used to mirror the system's boot drive from one physical disk to another, ensuring that the system remains running in the event that one of the physical disks fails. The PERC 4/IM controller firmware maintains the mirrored data on both physical disks so that the system's CPU is not burdened with the extra processing required to maintain the mirrored data.
When implementing mirroring on a PERC 4/IM controller, you use the controller BIOS to create a virtual disk from the physical disks. Unlike creating a virtual disk on other controllers, the PERC 4/IM controller is able to implement a mirror for a physical disk that already contains data. The data is then copied to the mirror. Any data previously residing on the mirror is overwritten.
After you have created the integrated mirror using the controller BIOS, the operating system sees the mirror as a virtual disk and a virtual disk object for the mirror is displayed in the Storage Management tree view. Expanding the Virtual Disks object displays the disks included in the mirror. These physical disks are no longer individually visible to the operating system.
On PERC 3/SC, 3/DCL, 3/DC, 3/QC, 4/SC, 4/DC, 4e/DC, 4/Di, 4e/Si, and 4e/Di 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 will automatically restart 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 non-RAID SCSI and SAS controllers are non-RAID controllers that support SCSI and SAS devices. Because these controllers are non-RAID, they do not support virtual disks. You can manage these non-RAID controllers and their attached SCSI and SAS devices with Storage Management.
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NOTE: Supported features may vary from controller to controller. |
The following non-RAID controllers use Small Computer System Interface (SCSI) technology.
The following non-RAID controllers use Serial Attached SCSI (SAS) technology.
Use this window to view information about the controller firmware and drivers. For more information on firmware and drivers, see "Installation Considerations for Storage Management".
The firmware and driver properties can vary depending on the model of the controller. On some controllers, Storage Management may not be able to obtain the driver or firmware version. In this case, Storage Management displays Not Applicable. Firmware and driver properties may include:
This screen displays the status of the controller and the components attached to the controller.
Component status is indicated by the severity. A component with a Warning or Critical/Failure status requires immediate attention to avoid data loss if possible. It may be useful to review the Alert Log for events indicating why a component has a Warning or Critical status. For additional troubleshooting information, see Alert Messages and Troubleshooting.
Severity |
Component Status |
---|---|
| Normal/OK. The component is working as expected. |
| Warning/Non-critical. A probe or other monitoring device has detected a reading for the component that is above or below the acceptable level. The component may still be functioning, but it could fail. The component may also be functioning in an impaired state. Data loss is possible. |
| Critical/Failure/Error. The component has either failed or failure is imminent. The component requires immediate attention and may need to be replaced. Data loss may have occurred. |
For information on the controller, see the following topics:
For information on attached components, see the following topics:
Use this window to view information about the controller and execute controller tasks.
The controller properties can vary depending on the model of the controller. Controller properties may include:
Property |
Definition | ||
---|---|---|---|
| These icons represent the severity or health of the storage component. See "Storage Component Severity" for more information. | ||
ID | This property displays the controller ID assigned to the controller by Storage Management. Storage Management numbers the controllers attached to the system starting with zero. This number is the same as the controller ID number reported by the "omreport Command". | ||
Name | This property displays the name of the controller. | ||
State | This property displays the current status of the controller. Possible values are: Ready The controller is functioning normally. Degraded The controller has suffered a failure and is operating in a degraded state. Failed The controller has suffered a failure and is no longer functioning. | ||
Firmware Version | This property displays the version of the firmware that is currently installed on the controller.
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Minimum Required Firmware Version | This property displays the minimum firmware version that is required by Storage Management. This property is only displayed if the controller firmware does not meet the minimum requirement. The firmware and drivers listed in the Readme file refer to the minimum supported version for these controllers. Later versions of the firmware and drivers are also supported. See the Dell Support website at support.dell.com for the most recent driver and firmware requirements. | ||
Driver Version | This property displays the version of the driver that is currently installed on the controller. The 2.8.0.6085 driver install package for the PERC 3/Si, and 3/Di controllers contains the 6076 driver. For this driver, Storage Management displays 2.8.0.6076 whereas Microsoft® Windows® Device Manager displays 2.8.0.6085.
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Minimum Required Driver Version | This property displays the minimum driver version that is required by Storage Management. This property is only displayed if the controller driver does not meet the minimum requirement. The firmware and drivers listed in the Readme file refer to the minimum supported version for these controllers. Later versions of the firmware and drivers are also supported. See the Dell Support website at support.dell.com for the most recent driver and firmware requirements. | ||
Number of Connectors | This property displays the number of connectors the controller has. Each connector can be attached to physical disks or an enclosure. Depending on the controller type, the connector can be either a SCSI channel or a SAS port. | ||
Rebuild Rate | The rebuild rate is the percentage of the system's resources dedicated to rebuilding a failed disk when a rebuild is necessary. See "Set Rebuild Rate" for more information. | ||
BGI Rate | The background initialization (BGI) rate is the percentage of the system's resources dedicated to performing the background initialization of a virtual disk after it is created. See "Set Background Initialization Rate" for more information. | ||
Check Consistency Rate | The check consistency rate is the percentage of the system's resources dedicated to performing a check consistency on a redundant virtual disk. See "Check Consistency" for more information. | ||
Reconstruct Rate | The reconstruct rate is the percentage of the system's resources dedicated to reconstructing a disk group after adding a physical disk or changing the RAID level of a virtual disk residing on the disk group. See "Set Reconstruct Rate" for more information. | ||
Alarm State | This property displays whether the controller's alarm is enabled or disabled. | ||
Cache Memory Size | This property displays the size of the controller's cache memory. | ||
Patrol Read Mode | This property displays the Patrol Read mode setting for the controller. Possible values are: Auto When set to Auto, a Patrol Read runs continuously on the system. When one iteration of the Patrol Read is complete, the next Patrol Read is scheduled to start within four hours. You do not have the option of manually starting or stopping the Patrol Read in Auto mode. Manual When set to Manual, you can start or stop the Patrol Read process. Disabled This property indicates that the Patrol Read process is disabled. For more information about Patrol Read, see: | ||
Patrol Read State | This property displays the current state of the Patrol Read process. Possible values are: Ready The Patrol Read process is enabled and will run when next scheduled or when manually initiated. Active The Patrol Read process is currently running. Stopped The Patrol Read has been stopped. For more information about Patrol Read, see "Set Patrol Read Mode". | ||
Patrol Read Iterations | This property displays the number of Patrol Read iterations. For more information about Patrol Read, see "Set Patrol Read Mode". | ||
Cluster Mode | This property indicates whether the controller is part of a cluster configuration. | ||
SCSI Initiator ID | This property displays the SCSI ID of a SCSI controller. The default value is usually 7. You can change the default value in the BIOS. In cluster mode, the value is 6 or 7. The SCSI ID is not displayed on the PERC 4/IM, PERC 3/Si, and 3/Di controllers. Use the BIOS on these controllers to identify the SCSI ID. |
Do the following to execute a controller task:
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NOTE: Different controllers support different features. For this reason, the tasks displayed on the Tasks drop-down menu can vary depending on which controller is selected in the tree view. If no tasks can be performed because of controller or system configuration limitations, then the Tasks drop-down menu displays No Task Available. |
On SCSI controllers, a rescan updates configuration changes (such as new or removed devices) for all components attached to the controller. For information on when you may want to do a rescan, see "Rescan to Update Storage Configuration Changes".
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NOTE: Rescan Controller is not supported on non-RAID SCSI controllers. You must reboot the system before Storage Management can see configuration changes on non-RAID SCSI controllers. Otherwise, configuration changes are not reflected in the Storage Management graphical user interface (GUI). |
Use the Create Virtual Disk task to launch the Create Virtual Disk Express Wizard. See "Create Virtual Disk Express Wizard (Step 1 of 2)" for more information.
Use the Enable Alarm task to enable the controller's alarm. When enabled, the alarm sounds in the event of a device failure.
Use the Disable Alarm task to disable the controller's alarm. When disabled, the alarm does not sound in the event of a device failure.
Use the Quiet Alarm task to quiet the controller's alarm when it is sounding. After it is quieted, the alarm is still enabled in the event of a future device failure.
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NOTE: The Quiet Alarm task is available on the PERC 3/SC, 3/DCL, 3/DC, 3/QC, 4/SC, 4/DC, 4e/DC, CERC ATA100/4ch, and the CERC SATA1.5/6ch controllers. |
Use the Test Alarm task to test whether the controller alarm is functional. The alarm will sound for about two seconds.
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NOTE: The Test Alarm task is only available on the CERC SATA1.5/6ch controller. |
Use the Set Rebuild Rate task to change the rebuild rate. See "Set Rebuild Rate" for more information.
Use the Reset Configuration task to erase all information on the controller, so that you can perform a fresh configuration. This operation destroys all virtual disks on the controller.
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NOTICE: Resetting a configuration permanently destroys all data on all virtual disks attached to the controller. If the system or boot partition resides on these virtual disks, it will be destroyed. |
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NOTE: Resetting the controller configuration does not remove a foreign configuration. To remove a foreign configuration, use the "Clear Foreign Configuration" task. |
Use this task to export the controller log to a text file. See "Export Log" for more information.
For information on attached components, see the following topics:
The Set Rebuild Rate task changes the controller's rebuild rate.
During a rebuild, the complete contents of a physical disk are reconstructed. The rebuild rate, configurable between 0% and 100%, represents the percentage of the system resources dedicated to rebuilding failed physical disks. At 0%, the rebuild will have the lowest priority for the controller, will take the most time to complete, and will be the setting with the least impact to system performance. A rebuild rate of 0% does not mean that the rebuild is stopped or paused.
At 100%, the rebuild will be the highest priority for the controller, will minimize the rebuild time, and will be the setting with the most impact to system performance.
On the PERC 3/SC, 3/DCL, 3/DC, 3/QC, 4/SC, 4/DC, 4e/DC, 4/Di, 4e/Si, 4e/Di, and CERC ATA100/4ch controllers, the controller firmware also uses the rebuild rate setting to control the system resource allocation for the following tasks. For these controllers, the rebuild rate setting applies to these tasks in the same manner that it applies to the Rebuild task.
Use the Reset Configuration task to erase all information on the controller so that you can perform a fresh configuration. This operation destroys all data and virtual disks on the controller and unassigns any hot spares.
You will need to completely reconfigure your storage after performing this operation.
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NOTICE: Resetting a configuration permanently destroys all data on all virtual disks attached to the controller. If the system or boot partition resides on these virtual disks, it will be destroyed. |
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NOTE: Resetting the controller configuration does not remove a foreign configuration. To remove a foreign configuration, use the "Clear Foreign Configuration" task. |
The Export Log task exports the controller log to a text file. The log gives detailed information on the controller activities and can be useful for troubleshooting.
On a Microsoft® Windows® system, the log file is exported to the windows or winnt directory. On a Linux system, the log file is exported to the /var/log directory.
Depending on the controller, the log file name will be either afa_<mmdd>.log or lsi_<mmdd>.log where <mmdd> is the month and date. For example, a log file exported on September 21 will be named either afa_0921.log or lsi_0921.log.
Exporting the controller log file clears the log file information from the controller log.
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NOTE: The Export Log File command is not supported on the PERC 4/IM, CERC ATA100/4ch, CERC SATA1.5/2s. In addition, some of the non-RAID SCSI controllers do not support the Export Log File command. |
Click Export Log File when ready. To exit without exporting the controller log file, click Go Back To Controller Information Page.
A foreign configuration is data residing on physical disks that have been moved from one enclosure to another or to a different controller. Virtual disks residing on physical disks that have been moved are considered to be a foreign configuration. Some controllers enable you to import a foreign configuration so that virtual disks are not lost after moving the physical disks.
To be imported, the foreign configuration must contain a virtual disk that is in either Ready or Degraded state. In other words, all of the virtual disk data must be present, but if the virtual disk is using a redundant RAID level, the additional redundant data does not need to be present.
For example, if the foreign configuration contains only one side of a mirror in a RAID 1 virtual disk, then the virtual disk is in Degraded state and can be imported. On the other hand, if the foreign configuration contains only one physical disk that was originally configured as a RAID 5 using three physical disks, then the RAID 5 virtual disk is failed and cannot be imported.
In addition to virtual disks, a foreign configuration may consist of a physical disk that was assigned as a hot spare on one controller and then moved to another controller. The Import Foreign Configuration task imports the new physical disk as a hot spare. If the physical disk was a dedicated hot spare on the previous controller, but the virtual disk to which the hot spare was assigned is no longer present in the foreign configuration, then the physical disk is imported as a global hot spare.
The Import Foreign Configuration task is only displayed when the controller has detected a foreign configuration. You can also identify whether or not a physical disk contains a foreign configuration (virtual disk or hot spare) by checking the physical disk state. If the physical disk state is Foreign, then the physical disk contains all or some portion of a virtual disk or has a hot spare assignment.
If you have an incomplete foreign configuration which cannot be imported, you can use the "Clear Foreign Configuration" task to erase the foreign data on the physical disks.
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NOTE: The import foreign configuration task imports all virtual disks residing on physical disks that have been added to the controller. If more than one foreign virtual disk is present, you cannot choose which one to import. All will be imported. |
Click Import Foreign Config when you are ready to import all virtual disks residing on physical disks that have been added to the controller. To exit without importing the foreign configuration, click Go Back To Controller Information Page.
After moving a physical disk from one controller to another, you may find that the physical disk contains all or some portion of a virtual disk (foreign configuration). You can identify whether or not a previously used physical disk contains a foreign configuration (virtual disk) by checking the physical disk state. If the physical disk state is Foreign, then the physical disk contains all or some portion of a virtual disk. Use the clear foreign configuration task to clear or erase the virtual disk information from the newly attached physical disks.
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NOTE: The clear foreign configuration task permanently destroys all data residing on the physical disks that have been added to the controller. If more than one foreign virtual disk is present, you cannot choose which one to clear. All will be cleared or erased. You may prefer to import the virtual disk rather than destroy the data. See "Import Foreign Configuration" for more information. |
Click Clear Foreign Config when you are ready to clear or erase all virtual disks residing on physical disks that have been added to the controller. To exit without clearing the foreign configuration, click Go Back To Controller Information Page.
The Set Background Initialization Rate task changes the amount of system resources dedicated to the background initialization task. See "Background Initialization on PERC 3/SC, 3/DCL, 3/DC, 3/QC, 4/SC, 4/DC, 4e/DC, 4/Di, 4e/Si, and 4e/Di Controllers" for more information on the background initialization task.
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 will have the lowest priority for the controller, will take the most time to complete, and will be 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 will be the highest priority for the controller, will minimize the background initialization time, and will be the setting with the most impact to system performance.
The Set Check Consistency Rate task changes the amount of system resources dedicated to the check consistency task. See "Check Consistency" for more information about the check consistency task.
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 will have the lowest priority for the controller, will take the most time to complete, and will be 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 will be the highest priority for the controller, will minimize the check consistency time, and will be the setting with the most impact to system performance.
The Set Reconstruct Rate task changes the amount of system resources dedicated to the reconstruct task.
The reconstruct task remakes the virtual disk after you have changed the RAID level or otherwise reconfigured the virtual disk. The reconstruct rate, configurable between 0% and 100%, represents the percentage of the system resources dedicated to running the reconstruct task. At 0%, the reconstruct will have the lowest priority for the controller, will take the most time to complete, and will be the setting with the least impact to system performance. A reconstruct rate of 0% does not mean that the reconstruct is stopped or paused.
At 100%, the reconstruct will be the highest priority for the controller, will minimize the reconstruct time, and will be the setting with the most impact to system performance.
Patrol Read is a feature for identifying disk errors in order to avoid disk failures and data loss or corruption. The Patrol Read only runs on disks that are being used in a virtual disk or that are hot spares.
When possible, the Patrol Read corrects disk errors and restores the integrity of the data. The Patrol Read task runs in the background. When the Patrol Read mode is set to Auto, the Patrol Read is initiated when the controller has been idle for a period of time and when no other background tasks are active. In this circumstance, the Patrol Read feature also enhances system performance as disk errors can be identified and corrected while the disk is not the subject of I/O activity.
The controller adjusts the amount of system resources dedicated to the Patrol Read based on the amount of controller activity that is competing with the Patrol Read task. During heavy controller activity, fewer system resources are dedicated to the Patrol Read task.
The Patrol Read will not run on a physical disk in the following circumstances:
In addition, the Patrol Read suspends during heavy I/O activity and resumes when the I/O is finished.
Click the radio button for the Patrol Read mode setting that you want to select: The possible settings are:
When the Patrol Read mode is set to manual, you can start the Patrol Read task or stop the task when it is running.
There are certain conditions under which the Patrol Read task cannot be run. See "Set Patrol Read Mode" for more information.
Click Start Patrol Read or Stop Patrol Read when ready. To exit without starting or stopping the Patrol Read, click Go Back To Controller Information Page.
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