A partitioner determines how data is distributed across the nodes in the cluster
(including replicas). Basically, a partitioner is a hash function for computing the token
(it's hash) of a row key. Each row of data is uniquely identified by a row key and
distributed across the cluster by the value of the token.
A snitch determines which data centers and racks are written to and read from.
Client read or write requests can go to any node in the cluster because all nodes in
Cassandra are peers.
Planning a cluster deployment
When planning a Cassandra cluster deployment, you should have a good idea of the initial
volume of data you plan to store and a good estimate of your typical application