Snitches

A snitch determines which datacenters and racks nodes belong to.

A snitch determines which datacenters and racks nodes belong to. Snitches inform the database about the network topology so requests are routed efficiently, and enable DataStax Distribution of Apache Cassandra™ (DDAC) to distribute replicas by grouping machines into datacenters and racks. Specifically, the replication strategy places the replicas based on the information provided by the new snitch. All nodes in a cluster must use the same snitch. Cassandra strives to not have more than one replica on the same rack (which is not necessarily a physical location).

Note: If you change snitches, you may need to perform additional steps because the snitch affects where replicas are placed. See Switching snitches.