Final: Question 1
Problems 1 through 3 are an exercise in running mongod’s, replica sets, and an exercise in testing of replica set rollbacks, which can occur when a former primary rejoins a set after it has previously had a failure.
Start a 3 member replica set (with default options for each member, all are peers). (a.sh will start the mongod’s for you if you like.)
$ # if on unix:
$ chmod +x a.sh
You will need to initiate the replica set yourself.