title: MongoDB datasize showing differences in show databases and DBPath
body: <p>Our MongoDB was created with replicaset, and the nodes went down due to some reason. Now after starting up its not starting up/ not able to find out the primary and secondary. From the logs we observed this error.
  "[rsSync] no valid sync sources found in current replset to do an initial sync"
  There is no way to promote one other nodes as primary, as the command needs to be run from primary database. Can anyone please suggest a way to bring the nodes up.</p>
  
  <p>Also, onething we noticed is the show databases command and size of DBPath is showing differences in size. Is there any backend mechanism running to keep the data compresses in the DB (something like gzipping the data in filesystem), or expand the data in the filesystem? Please advise on this.</p>