SIGMOD '90 Proceedings of the 1990 ACM SIGMOD international conference on Management of data
Analysis of file I/O traces in commercial computing environments
SIGMETRICS '92/PERFORMANCE '92 Proceedings of the 1992 ACM SIGMETRICS joint international conference on Measurement and modeling of computer systems
The architecture of a fault-tolerant cached RAID controller
ISCA '93 Proceedings of the 20th annual international symposium on computer architecture
RAID: high-performance, reliable secondary storage
ACM Computing Surveys (CSUR)
A performance study of three high availability data replication strategies
Distributed and Parallel Databases - Selected papers from the first international conference on parallel and distributed information systems
Scheduling algorithms for modern disk drives
SIGMETRICS '94 Proceedings of the 1994 ACM SIGMETRICS conference on Measurement and modeling of computer systems
Performance of RAID5 disk arrays with read and write caching
Distributed and Parallel Databases - Special issue on disk arrays
A Performance Evaluation of RAID Architectures
IEEE Transactions on Computers
An exact analysis on expected seeks in shadowed disks
Information Processing Letters
PDIS '91 Proceedings of the first international conference on Parallel and distributed information systems
Some new disk scheduling policies and their performance
SIGMETRICS '02 Proceedings of the 2002 ACM SIGMETRICS international conference on Measurement and modeling of computer systems
Computer Performance Modeling Handbook
Computer Performance Modeling Handbook
RAID5 Performance with Distributed Sparing
IEEE Transactions on Parallel and Distributed Systems
Freeblock Scheduling Outside of Disk Firmware
FAST '02 Proceedings of the Conference on File and Storage Technologies
VLDB '88 Proceedings of the 14th International Conference on Very Large Data Bases
Disk Mirroring with Alternating Deferred Updates
VLDB '93 Proceedings of the 19th International Conference on Very Large Data Bases
Simulation study of cached RAID5 designs
HPCA '95 Proceedings of the 1st IEEE Symposium on High-Performance Computer Architecture
A Performance Evaluation Tool for RAID Disk Arrays
QEST '04 Proceedings of the The Quantitative Evaluation of Systems, First International Conference
Comment on "Issues and Challenges in the Performance Analysis of Real Disk Arrays'
IEEE Transactions on Parallel and Distributed Systems
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Mirrored disks or RAID1 is a popular disk array paradigm, which in addition to fault-tolerance, doubles the data access bandwidth. This is important in view of rapidly increasing disk capacities and the slow improvement in disk access time. Caching of dirty data blocks in a non-volatile storage (NVS) cache allows the destaging of dirty blocks to be deferrable, so as to improve the response time of read requests by giving them a higher priority than write requests. Destaging of dirty blocks in batches to take advantage of disk geometry entails in lowered disk utilization due to writes and improved performance for reads. Polyzois et al. [12] propose a scheduling policy for mirrored disks equipped with an NVS cache, so that one disk processes read requests, while the other disk is processing a write batch according to the CSCAN policy. We propose an improved scheduling policy as follows: (i) eliminating the forced idleness caused by the batch processing paradigm for write requests, i.e., allowing write requests to be processed individually; (ii) using SATF or even an exhaustive search, to reduce destaging time compared to CSCAN; (iii) introducing a threshold for the number of read requests, which when exceeded defers the destaging of dirty blocks. We compare these two scheduling policies with each other and also against prioritizing the processing of reads versus writes: (i) the head-of-the-line (HOL) priority queueing discipline, (ii) SATF with conditional priorities. It follows from simulation results that the new method outperforms Polyzois' method, which is even outperformed by the HOL priority policy. SATF with conditional priorities slightly outperforms the proposed method from the viewpoint of its throughput and response time, but is susceptible to more variability in response time.