The Scotch Parallel Storage Systems (CMU-CS-95-107)

To meet the bandwidth needs of modern computer systems, parallel storage systems are evolving beyond RAID levels 1 through 5. The Parallel Data Lab at Carnegie Mellon University has constructed three Scotch parallel storage testbeds to explore and evaluate five directions in RAID evolution: first, the development of new RAID architectures to reduce the cost/performance penalty of maintaining redundant data; second, an extensible software framework for rapid prototyping of new architectures; third, mechanisms to reduce the complexity of and automate error-handling in RAID subsystems; fourth, a file system extension that allows serial programs to exploit parallel storage; and lastly, a parallel file system that extends the RAID advantages to distributed, parallel computing environments. This paper describes these five RAID evolutions and the testbeds in which they are being implemented and evaluated.