@manochpriyankara The memcached bucket is plain old memcached. So no internal replication , no persists to disk , no N1QL(SQL) queries on JSON data and no XDCR to another data center.
Why use memcached bucket then?
Maybe you need to use it as tmp data store with TTL(expires) of a few seconds or minutes.
But househippo I want the above features but no persist to disk.
In upcoming CB 5.0 release we have a new bucket type called ephemeral which does exactly that. SQL , XDCR , inter cluster replication but doesn’t write to disk. You can get a Beta of 5.0 here https://www.couchbase.com/downloads#couchbase-server