GitHub's MySQL infrastructure is essential for its operations, serving various functions such as GitHub.com, its API, and authentication, with every git request interacting with it. To maintain data availability and integrity, GitHub employs continuous testing and automation for tasks like backups, schema migrations, and failovers. Percona Xtrabackup is used for full and logical backups, ensuring data can be restored efficiently. Delayed replicas provide a safeguard against erroneous queries by allowing a rollback to a specific point in time. Failovers are tested in a production-like environment to ensure reliability, with orchestrator managing automated failovers. Chaos testing is being developed to further enhance resilience by intentionally disrupting the production environment in a controlled manner. For schema migrations, GitHub utilizes gh-ost to run live migrations, copying data onto ghost tables and swapping them with original tables after verification. This rigorous testing regime, including automated restore and failover tests, ensures high trust in the infrastructure's ability to handle ongoing and future challenges while accommodating continuous development and improvements.