Simon Willison’s Weblog

GitHub, by default, writes five replicas of each repository across our three data centers to protect against failures at the server, rack, network, and data center levels. When we need to update Git references, we briefly take a lock across all of the replicas in all of our data centers, and release the lock when our three-phase-commit (3PC) protocol reports success.

— Scott Arbeit

# 12:57 am / github