Ensembl is a joint project between the Sanger Institute and EMBL - European Bioinformatics Institute (EBI) to develop a software system which produces and maintains automatic annotation on selected eukaryotic genomes.

Ensembl releases all of its data into the public domain via a number of different sources, including a publicly available mysql database which contains the entire ensembl dataset (currently 2TB). The database handles 5 million queries and exports 20 Gbytes of data per day.

We use heartbeat to make the mysql service highly available. The database is hosted on a pair of dual Intel Xeon servers, with the data stored on a XFS file-system presented from our SAN. Heartbeat, via an APC MasterSwitch STONITH device, ensures that the database is only active on a single node at a time and provides fast fail-over in the case of hardware or network failures. Heartbeat enables scientists around the world to have continual access to Ensembl data.