Slides: https://www.slideshare.net/DataStax/how-cassandra-deletes-data-alain-rodriguez-the-last-pickle-cassandra-summit-2016 | How does Cassandra delete data when the files on disk are immutable? How does it make sure deletes are distributed around the cluster? The answer is Tombstones, a ""soft delete"" marker that solves these problems and creates others by inserting more data when you ask for data to be deleted. Which can result in serious problems for some data models, and headaches for developers and operations teams. With the correct settings and workload however it can mean that Cassandra efficiently removes old data from disk. In this talk Alain Rodriguez, Consultant at The Last Pickle, will explain why Cassandra uses tombstones, how they work, and when they are purged from disk. He will also discuss the best data models and configurations settings to ensure efficient purging, and what to do when it goes wrong. About the Speaker Alain Rodriguez Consultant, The Last Pickle Alain has been working with Apache Cassandra since version 0.8. He was the first Engineer at teads.tv which had grown to 400+ employees by the time he left. During his time at Teads Alain managed and scaled Cassandra clusters across multiple AWS Regions, fully on his own, taking care of the data modeling as well as the troubleshooting and tuning. Alain frequently contributes to the Apache Cassandra users mailing list.