Cassandra, MySQL, and HBase were evaluated for the Facebook new messaging system. HBase was finally picked and is now behind the new product announced today:
HBase comes with very good scalability and performance for this workload and a simpler consistency model than Cassandra. While we’ve done a lot of work on HBase itself over the past year, when we started we also found it to be the most feature rich in terms of our requirements (auto load balancing and failover, compression support, multiple shards per server, etc.). HDFS, the underlying filesystem used by HBase, provides several nice features such as replication, end-to-end checksums, and automatic rebalancing. Additionally, our technical teams already had a lot of development and operational expertise in HDFS from data processing with Hadoop. Since we started working on HBase, we’ve been focused on committing our changes back to HBase itself and working closely with the community. The open source release of HBase is what we’re running today.
Original title and link: Facebook: The Underlying Technology of Messages Using HBase (NoSQL databases © myNoSQL)