@Barada Nayak To acurately answer your question we need more info.
Which services do you plan to use (hive, oozie, hbase, etc)
Is HA required for all services? This is a business decision on HA requirements
what are the data volumes the cluster with host?
what are the mutation figures?
Generally you will find small clusters with 3 masters, medium with 4 and large with at least 5. It all depend on your use case. I have seen in the field where name node gets pounded and I have recommended to isolate the name node (not share with other master services).
