How to check secondary is synced now or not

Question

there is the replica with three member (primary,secondary,secondary). Suppose one of secondaries down for a day, after return secondary back to replica how can i find, i

Answer 1

Update 13th February 2017

Agree with the accepted answer that rs.status() offers adequate information and is an easy command to remember. However, (personally using Mongo 3 now), do also really like the convenience and readability of rs.printSlaveReplicationInfo().

It gives an output something like:

rs.printSlaveReplicationInfo()

source: node-2:27017
    syncedTo: Mon Feb 13 2017 06:15:17 GMT-0500 (EST)
    0 secs (0 hrs) behind the primary
source: node-3:27017
    syncedTo: Mon Feb 13 2017 06:15:16 GMT-0500 (EST)
    1 secs (0 hrs) behind the primary

As you can see, it is easy to get a sense of whether the synchronization between the nodes in the replica set is healthy or not.