Do we need to run 'repair' if new data center is added

3
votes

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.

1
cassandradatastax-enterpriserepair

1 Answers

4
votes

As you are adding the new DCs once you have changed the NetworkTopology replication factor to include the new DC a rebuild should be fine just make sure to specify the source DC as on of the preexisting DCs.

Here are detailed steps for adding a new DC.

In general you should be running a repair every week if you have the default GC Grace settings.