Chain Replication

What is CRAQ?

CRAQ (Chain Replication with Apportioned Queries) is a data-center focused storage system capable of good availability, high throughput, and low latency, while providing a sliding scale of read consistency operations (from eventual to strong consistency guarantees). Special consideration is given to high-performance support for cross-data-center replication, using geo-diversity for performance and fault-tolerance reasons.


  • Object Storage on CRAQ: High-throughput chain replication for read-mostly workloads.  Jeff Terrace and Michael J. Freedman.  Proc. USENIX Annual Technical Conference (USENIX ‘09),  San Diego, CA, June 2009. [pdf]


Special thanks to the National Science Foundation (CAREER award #0953197) for funding. None of the work described here reflects the opinions or positions of this organization.