cassandra-rackdc.properties file

Several snitch options use the cassandra-rackdc.properties configuration file to determine which datacenters and racks cluster nodes belong to. Information about the network topology allows requests to be routed efficiently and to distribute replicas evenly. The following snitches can be configured here:

GossipingPropertyFileSnitch
AWS EC2 single-region snitch
AWS EC2 multi-region snitch

The GossipingPropertyFileSnitch is recommended for production. This snitch uses the datacenter and rack information configured in a local node’s cassandra-rackdc.properties file and propagates the information to other nodes using gossip. It is the default snitch and the settings in this properties file are enabled.

The AWS EC2 snitches are configured for clusters in AWS. This snitch uses the cassandra-rackdc.properties options to designate one of two AWS EC2 datacenter and rack naming conventions:

legacy: Datacenter name is the part of the availability zone name preceding the last "-" when the zone ends in -1 and includes the number if not -1. Rack name is the portion of the availability zone name following the last "-".

Examples: us-west-1a ⇒ dc: us-west, rack: 1a; us-west-2b ⇒ dc: us-west-2, rack: 2b;
standard: Datacenter name is the standard AWS region name, including the number. Rack name is the region plus the availability zone letter.

Examples: us-west-1a ⇒ dc: us-west-1, rack: us-west-1a; us-west-2b ⇒ dc: us-west-2, rack: us-west-2b;