During the past year, we have been developing a write set replication system for MySQL/innodb engine, called Galera. Now, our project has reached milestone where we can run benchmarks to get performance metrics and also give out releases for public evaluation. In this blog, I'll give a short introduction to Galera and related projects.

Some Technology
Galera is generic multi-master synchronous replication system, which replicates transaction write sets at the commit time and resolves conflicts by comparing keys in write sets. Replication happens through group communication system, which (among other tasks) defines the order of committing transactions in the cluster. The write sets can carry original SQL statements or for best performance: row based replication events, available in MySQL 5.1 and onwards.

Galera replication method leaves the actual SQL statement processing to happen uninterrupted, and quite close …