title: Want to do an incremental backup for mongodb. Journaling? Oplog?
body: <p>I want to daily backups for a single mongodb database, probably with mongodump. To not lose any data, I would like this to be incremental so if something goes wrong in the middle of the day, I need to be able to replay changes for that day up til the point of failure after doing a mongorestore.</p>
  
  <p>Am I understanding correctly that I need to use an oplog for this? Or is journaling the answer? I tried doing the following:</p>
  
  <ol>
  <li>Turning my mongo database into a replica set of just one, so that it creates an oplog. (This feels pretty hacky)</li>
  <li>Restarting mongod with the --oplog option</li>
  <li>Performing changes that should be recorded in the oplog</li>
  </ol>
  
  <p>However nothing ever gets stored in the oplog. What is the best way to do such incremental backups? I'm basically looking for a similar approach to replaying the mysql binlog.</p>
  
  <p>Thanks</p>