Cisco MDS Fabric Merge Failure Case

We had ran a MDS fabric merge recently between MDS9509 and MDS9148 and met below two errors during the merging process. These errors could be avoided by configuring the correct setting which is detailed as below:


  • Domain ID Configuration

Error Message: %FCDOMAIN-2-EPORT_ISOLATED: %$VSAN 10%$ Isolation of interface port-channel10 (reason: configured domain ID is different from runtime domain ID)

From the log information, it is clear stated that the Domain ID is mis-matched between running-config and local switch configuration. One of the major reasons is the “fcdomain restart” command is not executed after setting the Domain ID. The “fcdomain restart” command basically applies your changes to the runtime settings and align the configured ID and running ID.

The Domain ID configuration could be checked with command “show fcdomain vsan 10” (VSAN 10 in my case).



  • NTP Setting

Error Message: %CFS-3-APP_MERGE_FAILED: Merge failed for app ntp, local switch WWN 20:00:00:xx:xx:xx:xx:xx, remote switch WWN 20:00:00:xx:xx:xx:xx:xy. Please check ‘show cfs merge status name ntp’ for more information.

The error is caused by the NTP configuration is mis-matched or conflicted.

The resolution is simplely to configure the same NTP setting as the peer switch and run “ntp commit”. Then, the NTP information will be compared and synced. You will get below information after the merge is a success by issuing command “show cfs merge status name ntp”

NTP Merge01


Some good reference documents are listed as below:

  • Cisco MDS SanOS Troubleshooting Guide — Troubleshooting Cisco Fabric Services–_Troubleshooting_Cisco_Fabric_Services

  • Troubleshooting Switch Level Issues and Interswitch Connectivity

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