2007 USENIX Annual Technical Conference
Pp. 129–142 of the Proceedings
Awarded Best Paper!
SafeStore: A Durable and Practical Storage System
Ramakrishna Kotla, Lorenzo Alvisi, and Mike Dahlin, The University of Texas at Austin
This paper presents SafeStore, a distributed storage system designed
to maintain long-term data durability despite conventional hardware
and software faults, environmental disruptions, and administrative
failures caused by human error or malice. The architecture of
SafeStore is based on fault isolation, which SafeStore applies
aggressively along administrative, physical, and temporal dimensions
by spreading data across autonomous storage service providers
(SSPs). However, current storage interfaces provided by SSPs are not
designed for high end-to-end durability. In this paper, we propose a
new storage system architecture that (1) spreads data efficiently
across autonomous SSPs using informed hierarchical erasure
coding that, for a given replication cost, provides several
additional 9's of durability over what can be achieved with existing
black-box SSP interfaces, (2) performs an efficient end-to-end audit
of SSPs to detect data loss that, for a 20% cost increase, improves
data durability by two 9's by reducing MTTR, and (3) offers durable
storage with cost, performance, and availability competitive with
traditional storage systems. We instantiate and evaluate these ideas
by building a SafeStore-based file system with an NFS-like interface.
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