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1 Abstract The performance of traditional RAID Level 5 arrays is, for many applications, unacceptably poor while one of its constituent disks is non-functional. This paper describes and evaluates mechanisms by which this disk array failure-recovery performance can be improved. The two key issues addressed are the data layout, the mapping by which data and(More)
We describe and evaluate a strategy for declustering the parity encoding in a redundant disk array. This akclustered parity organization balances cost against aizta reliability and performance during failure recovery. It is targeted at highly-available parity-based arrays for use in continuous-operation systems. It improves on standard parity organizations(More)
Parity encoded redundant disk arrays provide highly reliable, cost effective secondary storage with high performance for read accesses and large write accesses. Their performance on small writes, however, is much worse than mirrored disks—the traditional, highly reliable, but expensive organization for secondary storage. Unfortunately, small writes(More)
The complexity of advanced disk array architectures makes accurate representation necessary, arduous, and error-prone. In this paper, we present RAIDframe, an array framework that separates architectural policy from execution mechanism. RAIDframe facilitations rapid prototyping of new RAID architec-tures by localizing modifications and providing libraries(More)
This paper describes and evaluates two algorithms for performing on-line failure recovery (data reconstruction) in redundant disk arrays. It presents an implementation of disk-oriented reconstruction, a data recovery algorithm that allows the reconstruction process to absorb essentially all the disk bandwidth not consumed by the user processes , and then(More)
Parity-encoded redundant disk arrays provide highly reliable, cost-effective secondary storage with high performance for reads and large writes. Their performance on small writes, however, is much worse than mirrored disks—the traditional, highly reliable, but expensive organization for secondary storage. Unfortunately, small writes are a substantial(More)
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(More)