In order to see how much time your mongoDB slave is behind the primary node:

rs0:SECONDARY> db.printSlaveReplicationInfo()
 source: mongo.mongo.com:27017
     syncedTo: Mon Nov 12 2018 06:33:40 GMT+0000 (UTC)
     -4 secs (0 hrs) behind the primary

#mongodb #mongo #slave #printSlaveReplicationInfo #replica #replication