It is useful when analysing a logfile to search for "replSet" (case sensitively) to see the main replset related events. None of the following messages in db/repl/manager.cpp are found by these searches:

• "another primary seen with election time"
• "stepping down; another primary seen in replicaset"
• "stepping down; another primary was elected more recently"
• "another PRIMARY detected but it should step down since it was elected earlier than me"
• log() << "stepping down " << primary->fullName() << " (priority " << ...
• log() << "replset error could not reach/authenticate against any members" << endl;
• log() << "auth problems, relinquishing primary" << rsLog;
• log() << "can't see a majority of the set, relinquishing primary" << rsLog;
  Despite this, all are important events in the lifecycle of a replica set that are logged at the default logging level.