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Dell OpenManage Server Administrator Storage Management User's Guide
Channel Redundancy and Thermal Shutdown
Channel Redundancy on PERC 3/DCL, 3/DC, 3/QC, 4/DC, 4e/DC, 4/Di, and 4e/Di Controllers
Creating a Channel-redundant Virtual Disk
Connector Properties and Tasks
A controller contains one or more connectors (channels or ports) to which you can attach disks. A connector is externally accessible for attaching an enclosure (with external disks) to the system. A connector may also be attached to the system's backplane (for internal disks). The controller's connectors are displayed by expanding the controller object in the tree view.
It is possible to create a virtual disk that uses physical disks that are attached to different controller channels. The physical disks may reside in an external enclosure or the backplane (internal enclosure). If the virtual disk is maintaining redundant data on different channels, then the virtual disk is channel redundant. Channel redundancy means that if one of the channels fails, data will not be lost because redundant data resides on another channel.
Channel redundancy might also be used for disks that reside in enclosures subject to thermal shutdown. Should the enclosure attached to one of the channels shut down, redundant data is maintained on the other channel.
Channel redundancy is implemented by selecting physical disks on different channels when using the Create Virtual Disk Advanced Wizard.
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NOTE: Channel redundancy only applies to controllers that have more than one channel and that attach to an external disk enclosure. |
The following considerations apply when creating a channel-redundant virtual disk on these controllers:
The following instructions describe creating a virtual disk that uses channel redundancy.
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NOTE: Channel redundancy only applies to controllers that have more than one channel and that attach to an external disk enclosure. |
Recommended RAID Levels:
There are specific RAID level and configuration requirements for implementing channel redundancy. You must select the same number of physical disks on each channel that you use. Refer to "Number of Physical Disks per Virtual Disk" for information on the number of physical disks that can be used for different RAID levels. Refer to "Controller-supported RAID Levels" for information on controller-specific implementations of the RAID levels.
Depending on the controller type, use one of the following procedures when completing "Create Virtual Disk Advanced Wizard (Step 2 of 4)":
The following sections describe creating a channel-redundant virtual disk using RAID 10 or RAID 50 on a PERC 3/DCL, 3/DC, 3/QC, 4/DC, 4e/DC, 4/Di, or 4e/Di, controller.
RAID 10
RAID 50
The following section describes creating a channel-redundant virtual disk using RAID 10 or Concatenation of RAID 1 on a PERC 3/Di controller.
RAID 10 or Concatenation of RAID 1
This screen displays the status of the connector and the components attached to the connector.
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.
For information on the connector, see the following topics:
For information on attached components, see the following topics:
Use this window to view information about the connector and execute connector tasks.
The connector properties can vary depending on the model of the controller. Connector properties may include:
Property |
Definition |
---|---|
| These icons represent the severity or health of the storage component. See "Storage Component Severity" for more information. A Warning or Critical severity may indicate that the connector is unable to communicate with attached devices such as an enclosure. Check the status of attached devices. See "Cables Attached Correctly" and "Isolate Hardware Problems" for more information. |
Name | This property displays the connector number. |
State | This property displays the current status of the connector. Possible values are: Ready The connector is functioning normally. Degraded The connector has suffered a failure and is operating in a degraded state. Failed The connector has suffered a failure and is no longer functioning. |
Connector Type | This property displays whether the connector is operating in RAID or SCSI mode. Depending on the controller type, the connector can be either a SCSI connector or a SAS port. |
Termination | This property indicates the termination type of the connector. Narrow Indicates an 8 bit data bus. Wide Indicates a 16 bit data bus. Unknown Indicates that the termination type is unknown. Not Terminated On a SCSI controller, this property indicates that the data bus is not terminated. This property is also displayed when the termination type is unknown. |
SCSI Rate | This property displays the SCSI speed for a SCSI device. |
On a SCSI controller, this task rescans the controller connectors to verify the currently connected devices or to recognize new devices that have been added to the connectors. Performing a rescan on a connector is similar to performing a rescan on 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 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). |
Do the following to rescan a controller connector:
For information on attached components, see the following topics:
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