Grafana Cloud's upgrade from MySQL 5.7 to MySQL 8 was driven by the former's end-of-life and involved transitioning tens of thousands of customer databases across multiple servers and cloud providers. The migration emphasized minimal customer downtime, a small blast radius, and the ability to revert to the previous version if necessary. The team chose to use the mysqldump approach, allowing for selective database migrations with minimal disruption. The upgrade process revealed disk performance bottlenecks, leading to improvements that halved query execution times on busy servers. A phased rollout approach was employed across different environments and customer tiers, monitored through Grafana dashboards to track progress and resource utilization. Challenges such as deprecated MySQL variables, disk I/O bottlenecks, and unusually large databases were addressed, demonstrating the importance of incremental rollouts with the capability for quick rollbacks. The successful upgrade underscored the value of cautious, well-monitored deployment strategies.