There were internal warnings about making the move from highly customized MySQL bare-metal clusters to cloud infrastructure because of network latency, moving from physical machines to multi-tenant environments and having to rewrite a lot of their existing customization.
The other issue of trying to quietly move terabytes of information while the site is live hasn't helped either. Add in the challenge of keeping highly customized bare-metal databases in sync with a cloud environment isn't easy.
Its this very very very complex migration that's resulted in a lot of the ongoing issues.
https://hostingjournalist.com/news/microsoft-accelerates-git...
The migration underscores Microsoft’s strategy to unify its AI and developer ecosystems under Azure, bolstering performance and reliability for Copilot and related AI workloads. However, not all GitHub employees are confident in the transition. Internal concerns have surfaced about potential service disruptions, particularly given the complexity of moving GitHub’s massive MySQL clusters, which currently run on custom bare-metal infrastructure.
Outages have become more frequent in recent months, a symptom of GitHub’s growing operational strain. Insiders suggest the platform’s infrastructure - originally designed to handle conventional development workloads - is now being pushed to its limits by large-scale AI integrations and surging user activity.