Date of Original Version

5-2000

Type

Technical Report

Rights Management

All Rights Reserved

Abstract or Description

Freeblock scheduling is a new approach to utilizing more of a disk's potential media bandwidth. By filling rotational latency periods with useful media transfers, 20-50% of a never-idle disk's bandwidth can often be provided to background applications with no effect on foreground response times. This paper describes freeblock scheduling and demonstrates its value with simulation studies of two concrete applications: segment cleaning and data mining. Free segment cleaning often allows an LFS file system to maintain its ideal write performance when cleaning overheads would otherwise reduce performance by up to a factor of three. Free data mining can achieve over 47 full disk scans per day on an active transaction processing system, with no effect on its disk performance.

Comments

Superceded by Proceedings of the 4th Symposium on Operating Systems Design and Implementation, 2000.

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