The bridge to agent-scale Git infrastructure

Over the past year, while Git traffic grew exponentially, 99.99999% of the Git repositories on GitHub began living in two places at once: our own data centers and Azure. The rest are among the busiest on the platform, and they’re held back by just one thing: a 25ms round trip.

In an earlier blog post, we laid out the two principles behind our next-generation storage architecture:

In this post, we’ll look at the immediate bridge between our old design and our new one. We’ll talk about how a change to the way our quorum serializes writes gets the busiest repositories into Azure, and how that same step opens the door to replicas that keep no persistent state of their own.

The timing and shape of the move were driven by the agentic shift: rapidly growing traffic, a hard ceiling on the power capacity of our data centers and the surrounding geographical region, and physical supply chain constraints. …