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  1. Core Server
  2. SERVER-22030

Abort if oplog is uncapped when starting in repl mode

    • Type: Icon: Bug Bug
    • Resolution: Done
    • Priority: Icon: Critical - P2 Critical - P2
    • 3.2.13, 3.3.8
    • Affects Version/s: 3.0.7
    • Component/s: Replication
    • None
    • Minor Change
    • ALL
    • Repl 15 (06/03/16)

      In 3.0.7 (MMAPv1), oplog entries have been observed to be in non-monotonic order on secondaries where the oplog is not a capped collection.

      SERVER-20858 prevents non-capped oplogs from being created, however, this does not help if the system already has a non-capped oplog. However, in versions where SERVER-20858 isn't fixed, this is an easy situation to accidentally get into, eg. by following the oplog resize procedure but forgetting/missing the capped: true parameter, or just forgetting/missing the createCollection step entirely (the next step will create the (uncapped) collection when the last oplog entry is inserted).

      SERVER-20912 hints at a "preflight check". This ticket is to request that a startup warning be generated if --replSet is specified and a non-capped oplog is found. It would also be good to have rs.printReplicationInfo() print a warning if the oplog isn't capped. Both warnings should direct the user to resize their oplog.

            milkie@mongodb.com Eric Milkie
            kevin.pulo@mongodb.com Kevin Pulo
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