Mark Holland

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We describe and evaluate a strategy for declustering the parity encoding in a redundant disk array. This declustered parity organization balances cost against data reliability and performance during failure recovery. It is targeted at highly-available parity-based arrays for use in continuousoperation systems. It improves on standard parity organizations by(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 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 thedata layout, the mapping by which data and parity blocks(More)
The authors describe and evaluate two algorithms for performing online failure recovery (data reconstruction) in redundant disk arrays. 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, is presented, and this(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)
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 architectures by localizing modifications and providing libraries of(More)
There has been a profusion of studies related to the pathogenesis of antineutrophil cytoplasm antibody-associated small vessel vasculitis. Further definition of epitopes on the major antigens, proteinase-3 and myeloperoxidase, has been sought, and intracellular signal transduction pathways after antineutrophil cytoplasm antibody-neutrophil interactions are(More)