Consider my current Cassandra cluster is following, DC1: 2 DC2: 2 each data center has 2 nodes and RF=2. Now i am adding 2 more data centers DC1: 2, DC2:2 , DC3: 2, DC4 : 2. So is it required to run nodetool repair on new nodes in DC3 and DC4. So far i read executing nodetool rebuild in the new DC is enough.
Also, i have one more query on when to run 'nodetool repair'. Please advise me.