OpenAI · 2026
Rapidly scaling online storage to serve over 1 billion ChatGPT users (Part II)
OpenAI's Habitat storage platform went from one shared Azure Cosmos DB container, to dedicated single-tenant containers that pushed capacity planning onto every product team, and back to a shared container by default once Azure added hot-key throttling, request-priority QoS and a new serverless mode where each physical partition scales to 10K RU/s and splits on RU usage. After failover and failback outages in late 2024, OpenAI and Azure now co-own testing and monitoring. Replicating small latency-critical datasets widely, a Valkey lookaside cache invalidated through the Cosmos DB change feed, and a Rust rewrite of the proxy cut global read p50 from about 120 ms to about 10 ms.
1B+ users across 40 regions500+ PB served by Habitatmulti-tenancyhot key throttlingCDC cache invalidationAzure Cosmos DBValkeyKafka
Grab · 2026
App stability at scale with a layered defense
With many engineers and AI-assisted code landing in a weekly release of a superapp that has millions of lines of Android code, Grab stops crashes in layers. Lint rules (including custom ones written after post-mortems) and tests block merges, a mandatory one-week Grab Early Access build catches crashes before production, and a staged rollout over a week is automatically paused when the new version's crash rate looks abnormal. In production, on-call engineers first flip feature flags, then try server-side fixes, then hotfix, helped by a flag-rollout history dashboard and Crashlytics data exported to BigQuery.
millions of lines of Android code100M+ Google Play downloadsshift-left testingstaged rolloutfeature flagsAndroidiOSFirebase Crashlytics
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