Comment 4 for bug 1379706

Looks like the current command to get the lag is outdated, may be for MongoDB 1.x it was ok.

Now, in order to get replication lag It turns to be a complex solution. Here http://blog.mongolab.com/2013/03/replication-lag-the-facts-of-life/#How_do_I_measure_lag it is described how to measure the lag. Moreover, the lag has a different meaning, not like Seconds_behind_master in MySQL.