secondary namenode vs standby namenode code example

Example: secondary namenode vs standby namenode

Bigdata: 
secondary namenode vs standby namenode:

The duties of standby namenode is similar to Secondary namenode 
where it keeps the track of active namenode activity and take snapshot 
periodically. Here, in case of active namenode failure, 
standby namenode automatically takes the control and becomes active. 
This way user will not notice the failure in namenode