An Analytic Behavior Model for Disk Drives with Readahead Caches and Request Reordering

Modern disk drives read-ahead data and reorder incoming requests in a workload-dependent fashion. This improves their performance, but makes simple analytical models of them inadequate for performance prediction, capacity planning, workload balancing, and so on. To address this problem we have developed a new analytic model for disk drives that do readahead and request reordering. We did so by developing performance models of the disk drive components (queues, caches, and the disk mechanism) and a workload transformation technique for composing them. Our model includes the e ects of workload-speci c parameters such as request size and spatial locality. The result is capable of predicting the behavior of a variety of real-world devices to within 17% across a variety of workloads and disk drives. 1 Motivation There are many reasons for wanting analytical performance models of disk drives and other storage devices. In our case, we were working to develop an automatic attribute-managed st...

• Type: Conference
• Year: 1998
• Where: SIGMETRICS
• Authors: Elizabeth A. M. Shriver, Arif Merchant, John Wilkes
• Keywords: Disk Drives, Hardware, Performance Model, Performance Prediction, SIGMETRICS 1998