Monitors the performance of reads from the various replicas and chooses the best replica based on this history.

By default, all snitches use a dynamic snitch layer that monitors read latency and, when possible, routes requests away from poorly-performing nodes. The dynamic snitch is enabled by default and is recommended for use in most deployments. For information on how this works, see the Dynamic snitching in Cassandra: past, present, and future blog post. Configure dynamic snitch thresholds for each node in the cassandra.yaml configuration file. Also, see the properties listed under About failure detection and recovery.