Dedicated Mirror Channel Failed

What Caused the Problem?

A dedicated cache mirroring channel has failed. The Recovery Guru Details area provides specific information you will need as you follow the Recovery Steps.

Caution: Electrostatic discharge can damage sensitive components. Always use proper antistatic protection when handling components. Touch components without using a proper ground may damage the equipment.

Caution: Possible loss of data accessibility. Do not remove a component when either (1) the Service action (removal) allowed (SAA) field in the Details area of this recovery procedure is NO (), or (2) the SAA LED on the affected component is OFF (note that some products do not have SAA LEDs). Removing a component while its SAA LED is OFF may result in temporary loss of access to your data. Refer to the following Important Notes and the Recovery Steps for more detail.

Important Notes

The purpose of the dedicated cache mirror channel is to increase the performance of mirroring cached data between the two RAID controller modules.
This problem can result from a problem with a dedicated mirror channel inside one of the following hardware components:
- RAID Controller Module (A or B)
- Interconnect-battery module (if applicable for your model of RAID controller module enclosure)
If the failure is determined to be in a RAID controller module, then that RAID controller module will have a Degraded status in the Physical View of the Array Management Window and in the Storage Array Profile.
There can be one or more dedicated mirror channels per RAID controller module. If all of the dedicated mirror channels fail, then write caching for all virtual disks will be automatically suspended. Write caching will be reinstated after the failed component has been replaced (see the Recovery Steps below).
Service Action Allowed Important Information:
- The Service action (removal) allowed field in the Details area indicates whether or not you can safely remove the component. If the SAA field is NO (), then the affected component must remain in place until you service another component first.
- The Service action LED on Component field in the Details area indicates whether or not a physical SAA LED is present on the hardware component. This field does NOT indicate whether the LED is ON or OFF (that indication is provided by the Service action (removal) allowed field).
- If a component does not have an SAA LED, then it is OK to remove the component when its fault LED is lit and the Service action (removal) allowed field = YES () in the Details area.
- The Service action (removal) allowed field shown in the Details area and the physical SAA LED on the hardware component (if supported) MUST match before you remove the affected component. In rare cases (such as multiple problems), the status of the LED and the SAA field may not match. If there is a mismatch, then you should NOT remove the component until these indications match. The Recovery Steps will help you to make this determination.

Recovery Steps

Refer to the 'Component requiring service' field in the Details area to determine which procedure you need to complete.

If...	Then...
The component that requires service is a RAID controller module	Go to "Procedure for Replacing a RAID Controller Module."
The component that requires service field displays "Unknown"	The problem cannot be traced to a particular component. The problem can be with either RAID Controller Module A, RAID Controller Module B, or with the Interconnect-Battery Module. It is recommended that you contact your technical support representative to assist you with resolving this problem. Do not continue with the remaining Recovery Steps until instructed to do so by your technical support representative. Advanced users only: If you have a spare RAID controller module or interconnect-battery module, you can use the spares to replace the components to determine if the problem is resolved. Use the steps provided in "Procedure for Replacing a RAID Controller Module" to replace RAID Controller Module A first, then RAID Controller Module B, and then use the steps provided in "Procedure for Replacing an Interconnect-Battery Module" to replace the Interconnect-Battery module (if applicable for your model of RAID controller module enclosure). After replacing each component, click the Recheck button in the Recovery Guru to determine if the problem has been fixed.

Procedure for Replacing a RAID Controller Module

If there are any hosts connected to this storage array that are NOT running a host-based, multi-path failover driver, stop I/O to the storage array from each of these hosts.

Place the affected RAID controller module offline. The affected RAID controller module is listed in the 'Component requiring service' field in the Details area.

a	Select the RAID controller module in the Physical View of the Array Management Window.
b	Select Advanced >> Recovery >> Set RAID Controller Module >> Offline.
c	Complete the instructions in the dialog, then select Yes.

Read all of the following steps before taking any action. The remaining Recovery Steps will no longer be accessible from the Recovery Guru dialog after you complete step a.

a	Click the Recheck button to rerun the Recovery Guru.
b	Select the "Offline RAID Controller Module" problem that is being reported in the Summary area.
c	Complete the Recovery Steps in the "Offline RAID Controller Module" recovery procedure to replace the affected RAID controller module.

Procedure for Replacing an Interconnect-Battery Module

Obtain a replacement Interconnect-battery module with the same part number as the failed one.

Note: The part number of the Interconnect-battery module can be located in the Storage Array Profile or in the View Enclosure Components dialog.

Prepare the Interconnect-battery module for removal by completing the following steps:

Select the Advanced >> Troubleshooting >> Prepare for Removal menu option.

Select the appropriate Enclosure (as listed in the Details area) and then the Interconnect-battery module from the respective drop-down menus.

Click the Prepare for Removal button.

If...

Then...

The resulting dialog indicates that the component is safe to remove

Go to step 3.

The resulting dialog indicated that the component is NOT safe to remove

Answer the following question:

Are there other problems being reported in the Summary area?

Yes - Fix these problems first and then return to this procedure after clicking the Recheck button.
No - Stop this procedure and contact your technical support representative

Remove the Interconnect-battery module.

If...

Then...

This storage array is configured to operate without batteries

Make sure that the new module does not contain batteries, otherwise the storage array will have a Needs Attention status if it is inserted with batteries.

Go to step 4.

This storage array is configured to operate with batteries

If...	Then...
The new module contains batteries	Go to step 4.
The new module does NOT contain batteries	Remove the batteries from the failed module and insert them into the new module. Go to step 4.

Insert the new replacement Interconnect-battery module and be sure that the module is securely seated.

Click the Recheck button to rerun the Recovery Guru. The failure should no longer appear in the Summary area. If the failure appears again, contact your technical support representative.