GitHub's gh-ost is a MySQL online schema migration tool changing the operational paradigm. It is triggerless, controllable, auditable, and generates a low writeload on the master.

This session describes how gh-ost differs from existing online schema migration tools, and the many perks made available by its design.

gh-ost runs all of GitHub's migrations. It is released as open source and supported by GitHub at https://github.com/github/gh-ost