cassandra-rackdc.properties file

Configuration file for the GossipingPropertyFileSnitch, Ec2Snitch, and Ec2MultiRegionSnitch.

cassandra-rackdc.properties

The location of the cassandra-rackdc.properties file depends on the type of installation:

Package installations	/etc/dse/cassandra/cassandra-rackdc.properties
Tarball installations	`installation_location`/resources/cassandra/conf/cassandra-rackdc.properties

The GossipingPropertyFileSnitch, Ec2Snitch, and Ec2MultiRegionSnitch use the configuration file to determine which datacenters and racks nodes belong to. They inform the database about the network topology to route requests efficiently and distribute replicas evenly. Settings for this file depend on the type of snitch:

This page also includes instructions for migrating from the PropertyFileSnitch to the GossipingPropertyFileSnitch.

GossipingPropertyFileSnitch

This snitch is recommended for production. It uses rack and datacenter information for the local node defined in the cassandra-rackdc.properties file and propagates this information to other nodes via gossip.

To configure a node to use GossipingPropertyFileSnitch, edit the cassandra-rackdc.properties file as follows:

Define the datacenter and rack that include this node. The default settings:
```
dc=DC1
rack=RAC1
```
Note: datacenter and rack names are case-sensitive. For examples, see and .
To save bandwidth, add the prefer_local=true option. This option tells DataStax Enterprise to use the local IP address when communication is not across different datacenters.

PropertyFileSnitch and GossipingPropertyFileSnitch considerations

Understanding the PropertyFileSnitch and the GossipingPropertyFileSnitch requires background information about their behavior across DSE releases. For important details, refer to this Tip in the Switching Snitches topic.