MongoDB Documentation, Release 3.0.4 { "_id" : "rs", "version" : 7, "members" : [ { "_id" : 0, "host" : "mongod_A.example.net:27017" }, { "_id" : 1, "host" : "mongod_B.example.net:27017" }, { "_id" : 2, "host" : "mongod_C.example.net:27017" } ] } { "_id" : "rs", "version" : 8, "members" : [ { "_id" : 0, "host" : "mongod_A.example.net:27017" }, { "_id" : 1, "host" : "mongod_B.example.net:27017" } ] } 6. Overwrite the replica set configuration document with the new configuration by issuing the following: 7. To confirm the new configuration, issue rs.conf() . 5. Modify the cfg object to remove the member. 4. Assign the current configuration document to the variable cfg : Example cfg = rs.conf() To remove mongod_C.example.net:27017 use the following JavaScript operation: cfg.members.splice(2,1) rs.reconfig(cfg) As a result of rs.reconfig() the shell will disconnect while the replica set renegotiates which member is primary. The shell displays a DBClientCursor::init call() failed error even though the com- mand succeeds, and will automatically reconnected. For the example above the output would be: 619 9.3. Replica Set Tutorials