Cassandra is an elastically scalable, distributed, redundant and highly-available column store. Recent versions of Cassandra added support for compare-and-swap operations via lightweight
transactions using an implementation of the Paxos protocol. Datomic leverages this mechanism to manage a small number of keys per database that require coordinated access, while the bulk of a database's content is written as immutable data to a quorum of replicas in the cluster.
Cassandra support requires a minimum Apache Cassandra 2.0.2 or newer, or equivalent. Native CQL protocol support must be enabled. Cross-data center deployments are not supported. Cassandra internal security is supported, but optional.
This release represents preliminary support based on requests from users. We are very interested in feedback.
For instructions on configuring Cassandra for use with Datomic, see Setting Up Storage Services.