Do I need a three-node cluster for Cassandra?

Anne Ramey

For production, yes; for development a single node can be used. Why? A two node cluster does not provide an adequate “majority” necessary for Cassandra’s distributed nature. If development only uses a single node, it loses out on the opportunity to be recovered by simply adding a new node. Additionally, performance has the potential to vary greatly when using a different number of nodes or datacenters, and using similar configurations has diagnostic advantages.