How to set featureCompatibilityVersion on secondary replica set member which does not startup due to this error? I am basically trying to resync a broken secondary. I have removed all the data and restarted the service but keep getting this error. I can see that featureCompatibilityVersion is set to 3.6 which the other are set to 3.4. I know this from starting the server up outside the set. However the second I add the server to replica set again I get the same error meaning I can’t change featureCompatibilityVersion to 3.4 since the server will not start. How do I fix this this catch 22 situation? Do I have to remove auth settings during syncing?
Thanks in advance for any help.
----Error
Initial sync attempt failed – attempts left: 9 cause: IncompatibleServerVersion: Sync source had unsafe feature compatibility version: downgrading to 3.4
2020-02-11T15:46:56.115+0000 I REPL [replication-1] Initial Sync Attempt Statistics: { failedInitialSyncAttempts: 1, maxFailedInitialSyncAttempts: 10, initialSyncStart: new Date(1581436015001), initialSyncAttempts: [ { durationMillis: 0, status: “IncompatibleServerVersion: Sync source had unsafe feature compatibility version: downgrading to 3.4”, syncSource: “10.35.5.65:27017” } ] }