Cassandra Data Replication problem

Question

I have a 2 node cassandra cluster with a replication factor of 2 and AutoBootStrap=true. Everything is good during startup and both nodes see each other. Let us call these nodes

Answer 1

There are 3 ways cassandra syncs updates that happened while a node was down:

1. hinted handoff. requires that failure detector on A recognize that B is down before you write K2. See http://wiki.apache.org/cassandra/HintedHandoff
2. read repair. requires that B be up when K2 is requested for the repair to happen. See http://wiki.apache.org/cassandra/ReadRepair
3. anti-entropy repair. requires invoking manually ("nodetool repair"). see http://wiki.apache.org/cassandra/AntiEntropy