Cassandra as a primary data store for Elasticsearch
Cassandra [2] commitlogs, backup and restore ensure durability for Elasticseach[1].
Cross datacenter replication for Elasticsearch
Cassandra [2] asynchronous replication allow to synchronize many Elasticsearch[1] clusters sharing the same mapping.
Realtime Search and Analytics with Cassandra
Elasticsearch [1] API, plugins and tools like Kibana [1] provide additional features to cassandra.
[1] Elasticsearch and Kibana are registered trademarks of Elasticsearch BV.
[2] Apache Cassandra, Apache, and Cassandra are trademarks of the Apache Software Foundation.