Faulty Or Inaccessible Mapped LUNs Due to Faulty Mirror Channels

Publication Date:  2012-07-22 Views:  185 Downloads:  0
Issue Description

The indicators of a storage device are lit on correctly. By checking the ISM, the current status of the device is normal. However, error messages and prompts saying unable to read/write occur when accessing mapped LUNs on the AS.

Product and version information:
  • S2600
  • S5000 series
  • The OS of the AS node is AIX
Alarm Information
None
Handling Process
Set the rate of mirror channels to 2G, or contact technical support for replacing controller enclosures.
 CAUTION:
  • This problem can be avoided by reconfiguring the Write Strategy of controller B as Write Back and No Mirroring.
  • If it is necessary to set the rate of mirror channels to 2G, please make sure the mirror I/O of the service is smaller than 200 Mbit/s.

 

Root Cause
  1. It is found the LUN that cannot be accessed (or is faulty) is the only one that is owned by controller B.
  2. Also, it is found that the LUN cannot be mounted if it is in the "unmount" state when running the command mount on the AS.
  3. In the ISM, reconfigure the owning controller of the LUN as controller A.
  4. Run the command mount on the AS again to make sure the LUN can be properly mounted.

Conclusion:

  • The LUNs mapped to the AS throw out error messages or are inaccessible when faulty mirror channels occur for controller enclosures.
Suggestions
None

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