3PAR luns not visible at host end

[Niveda]

Hi All,

We have 7200c 3PAR which had gone down due to unplanned power outage on saturday and went it came up,we had a bad node. Also the luns presented to 6 node cluster was not visible to host end.We replaced the node but still the same issue. 3PAR now looks okay ,SAN is okay but the issue still remains.

Tried to map a Test lun to a standalone server attached to 3PAR,it came visible but another test lun to cluster isnt.When I add the standalone server to cluster ,the test lun disappeared. Ive rebooted 3PAR ,restarted brocade switches ,also the hosts but no luck.

Showvlun shows the volumes are in transit rather being active. Any idea about this behaviour. Any help or suggestions be appreciated.

Thanks

[Amjad_kasem]

It seems you're facing a complex issue with your 3PAR storage system, SAN connectivity, and possibly host configuration. Here’s a straightforward approach to help diagnose and resolve the problem:

1. Check 3PAR Configuration:

   • Verify Volume Status: Use the showvlun command to check the status of your LUNs. If they’re listed as in transit, this might point to a configuration or connectivity problem.
   • Check LUN Mapping: Ensure that your LUNs are properly mapped to the host cluster. Commands like showvv and showvlun can help you confirm this.

2. Host Configuration:

   • Check Host Setup: Make sure the cluster configuration is correct and all nodes are set up to see the LUNs.
   • Verify Multipath Configuration: Ensure that the multipath software on your hosts is correctly configured. A misconfigured setup can cause visibility issues.
   • Check Host Connectivity: Use tools like diskpart or lsblk (on Linux) to ensure the host is detecting the SAN storage.

3. SAN Switch Configuration:

   • Check Switch Setup: Verify that your SAN switches are correctly configured and that zoning is properly set. Incorrect zoning can prevent LUN visibility.
   • Check Switch Logs: Look at the logs on your Brocade switches for any errors or warnings that might indicate a problem.

4. Cluster and Node Checks:

   • Verify Cluster Health: Make sure all nodes in the cluster are healthy and communicating properly. Issues with the cluster configuration can affect LUN visibility.
   • Check Node Status: Ensure that the replacement node has been fully integrated into the cluster and is functioning correctly.

5. Software and Firmware:

   • Check for Updates: Ensure that your 3PAR firmware and software are up-to-date. Sometimes, bugs or compatibility issues can affect LUN visibility.
   • Review Logs and Alerts: Examine 3PAR logs and system alerts for additional information about the issue.

6. Additional Troubleshooting:

   • Re-check LUN Presentation: Try re-presenting the LUNs to the hosts. This can sometimes resolve visibility issues.
   • Test with Different Hosts: As you did with the standalone server, test with different hosts to determine if the issue is specific to a particular host or configuration.

By following these steps, you should be able to narrow down the cause of the problem and work towards a solution

[Mahesh202 · Accepted solution]

Hi Niveda

I would suggest you try the below command

"setrcopygroup override"
This will set the policy of the Remote Copy volume group for dealing with I/O failure and error handling also it switches the direction of transfer between volume groups. 
It will override the failsafe state which is applied to the Remote Copy group, allowing the associated volumes to be exported to attached hosts.

Hope this helps.!!

Regards
Mahesh.

[Niveda]

It did work.

Thank you

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[Mahesh202]

Hi Niveda

I am glad to hear that the command I shared was helpful and that it worked for you. Please let me know if you have any further questions.

Regards
Mahesh

[Niveda]

@Mahesh202 Thanks much Mahesh. I really appreciate your help.

I also see alerts like this:
Alert sw_rmm_volume:531:xxxIxxPCLxxxxxB.r Remote Copy Volume 531xxxIxxPCLxxxxxB.r) Degraded (Volume Unsynced - requires a full resync since ldck is in progress {0xa})
Alert sw_rmm_volume:532:xxxPCxxxXML_Inter.r Remote Copy Volume 532(xxxPCxxxXML_Inter.r ) Degraded (Volume Unsynced - requires a full resync since ldck is in progress {0xa})

Does it need me to do anything

Let me know please

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[Niveda]

Also the volumes the moment after it had come visible in server disk management,went to paused state for sometime. Do you think the storage had caused this.

Thanks in advance

[Mahesh202]

Hi Niveda

Please connect to the SP or array directly and run a healthcheck (healthcheck -svc -detail) to get details.

the 'Degraded' error can be for several reasons, since "ldck is in progress" I would suggest you get in touch with the HPE 3PAR Tech support team analyze the logs and get the issue resolved.

Regards
Mahesh.

[support_s]

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