Wide-area cooperative storage with CFS

• Main Authors: DABEK, Frank, KAASHOEK, M. Frans, KARGER, David, MORRIS, Robert, STOICA, Ion
• Format: Conference Proceeding
• Language: English
• Subjects: Applied sciences; Computer science; control theory; systems; Exact sciences and technology; Memory and file management (including protection and security); Memory organisation. Data processing; Software; Telecommunications; Telecommunications and information theory; Teleprocessing networks. Isdn
• ISSN: 0163-5980; 1943-586X
• DOI: 10.1145/502059.502054

The Cooperative File System (CFS) is a new peer-to-peer read-only storage system that provides provable guarantees for the efficiency, robustness, and load-balance of file storage and retrieval. CFS does this with a completely decentralized architecture that can scale to large systems. CFS servers provide a distributed hash table (DHash) for block storage. CFS clients interpret DHash blocks as a file system. DHash distributes and caches blocks at a fine granularity to achieve load balance, uses replication for robustness, and decreases latency with server selection. DHash finds blocks using the Chord location protocol, which operates in time logarithmic in the number of servers.CFS is implemented using the SFS file system toolkit and runs on Linux, OpenBSD, and FreeBSD. Experience on a globally deployed prototype shows that CFS delivers data to clients as fast as FTP. Controlled tests show that CFS is scalable: with 4,096 servers, looking up a block of data involves contacting only seven servers. The tests also demonstrate nearly perfect robustness and unimpaired performance even when as many as half the servers fail.