OpenAI · 2026
Scaling Git at OpenAI
OpenAI built Pando, a Git-compatible backend for its monorepo after Codex pushed concurrent branches, merges and fetches past the old system (reliability sometimes below 90%). Pando stores each push as an immutable pack in blob storage and records per-branch ref versions in a horizontally scalable metadata store, giving serializability per ref and causal consistency across the repo so unrelated branches do not contend. Instead of building unique packs per client, it reuses stored packs and serves them via packfile-uri through regional Express caches (over 99% hit rate), with LSM-style background compaction so fetches plan in logarithmic time. Deployed first as a read/write-through proxy, then cut over with a Git CLI wrapper; it now powers all monorepo development, cut median push latency by nearly 5x, and can deliver nearly a petabyte of Git data per day (57+ TB in a single hour).
nearly a petabyte of Git data/daymedian push latency cut nearly 5x (~80%)per-ref causal consistencyreusable packfilesstorage/compute separationGitPandoRust
GitHub · 2026
The bridge to agent-scale Git infrastructure
GitHub has copied 99.99999% of its Git repositories to Azure, where most now keep two of their five replicas and Azure serves about half of Git traffic. The busiest remaining repositories were blocked by a ~25ms cross-region round trip, because Spokes held a repository-wide lock for each write while waiting on the slowest healthy replica. Scoping the quorum to individual Git references lets writes to different branches proceed in parallel (3-4x higher throughput in internal testing), and a virtual write replica that streams writes into Azure Blob Storage lets stateless read replicas scale out on demand.
99.99999% of repositories copied to AzureAzure serves about half of Git trafficper-reference quorumstorage/compute separationcloud migrationGitSpokesAzure
GitHub · 2026
Building Git infrastructure for agent-scale development
GitHub explains why agent workloads strain Spokes, which keeps five durable copies of each repo on fileserver disks, so every added read replica slows writes. The new design coordinates only the ref update, moves compaction and GC to separate workers, and separates storage from compute: Azure Blob Storage holds the authoritative data while lightweight caching workers serve reads.
473.3 billion Git events/month7.38 billion commits in Sept 2026control plane separationread replicascachingGitSpokesAzure Blob Storage