US Patent 8996467 Distributed scalable deduplicated data backup system

A distributed, cloud-based storage system provides a reliable, deduplicated, scalable and high performance backup service to heterogeneous clients that connect to it via a communications network. The distributed cloud-based storage system guarantees consistent and reliable data storage while using structured storage that lacks ACID compliance. Consistency and reliability are guaranteed using a system that includes: 1) back references from shared objects to referring objects, 2) safe orders of operation for object deletion and creation, 3) and simultaneous access to shared resources through sub-resources.