Twitter from MySql to Cassandra

Twitter, the world's most famous Microblogging service picked Cassandra as alternative to its MySql database system.

Cassandra is a no-sql open source distributed database management system. One of the top-level Apache Software Foundation projects, written in Java and first developed by Facebook to develop their Inbox Search features.

The choice will provide Twitter with a fault-tolerant and more decentralized system that can be run on large server clusters and is capable of taking in very large amounts of data at a time. Data is self-replicated within multiple nodes in and across data centers to allow replacement of failed data with no downtime.

Ryan King, Systems Engineer at Twitter, said that the previous system consisting of MySql and memcached became very costly in terms of manpower to operate, he stressed that Twitter needs a system that can grow in a more automated fashion and be highly available. The top reasons for going with Cassandra were no single points of failure, highly scalable writes and a healthy and productive open source community.

In addition to Twitter and Facebbok, both Digg and WebEx are using Cassandra, an option that is becoming more popular in current web services.