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  1. Core Server
  2. SERVER-34342

FCV is "3.2" for new 3.4 replica set with clusterMode: shardsvr

    • Type: Icon: Bug Bug
    • Resolution: Works as Designed
    • Priority: Icon: Minor - P4 Minor - P4
    • None
    • Affects Version/s: 3.4.14
    • Component/s: Sharding, Upgrade/Downgrade
    • Labels:
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    • ALL
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      • Create a 3.4.14 single member replica set with sharding.clusterRole: shardsvr, with no data so it's brand new, for example:
      processManagement:
        fork: true
      
      storage:
        dbPath: data/m1
        journal:
          enabled: true
      
      systemLog:
        destination: file
        path: data/m1.log
      
      replication:
        replSetName: rs
      
      sharding:
        clusterRole: shardsvr
      
      • Connect with mongo shell and rs.initiate()
      • Run db.adminCommand( {getParameter: 1, featureCompatibilityVersion: 1 }

        )

      output is:

      { "featureCompatibilityVersion" : "3.2", "ok" : 1 }
      

      Expected output is that the FCV is "3.4" as this is a new replica set.

      Show
      Create a 3.4.14 single member replica set with sharding.clusterRole: shardsvr , with no data so it's brand new, for example: processManagement: fork: true storage: dbPath: data/m1 journal: enabled: true systemLog: destination: file path: data/m1.log replication: replSetName: rs sharding: clusterRole: shardsvr Connect with mongo shell and rs.initiate() Run db.adminCommand( {getParameter: 1, featureCompatibilityVersion: 1 } ) output is: { "featureCompatibilityVersion" : "3.2", "ok" : 1 } Expected output is that the FCV is "3.4" as this is a new replica set.

      Starting a new single member 3.4.14 replica set with no data, and the configuration includes sharding.clusterRole: shardsvr, causes the featureCompatibilityVersion to be reported as "3.2".

      Removing the sharding.clusterRole: shardsvr option and restarting the mongod does not change the FCV to "3.4".

      However starting a new single member replica set (no data) without shardsvr works correctly, showing FCV of "3.4", and restarting it with shardsvr also still shows FCV of "3.4".

      Note that there is no FCV document in admin.system.version during all this. Running setFeatureCompatibilityVersion: "3.4" works to set the FCV to 3.4, so this issue is only about what FCV is assumed when you start a brand new replica set.

            Assignee:
            Unassigned Unassigned
            Reporter:
            spencer.brown@mongodb.com Spencer Brown
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              Created:
              Updated:
              Resolved: