SAIL: Self-adaptive file reallocation on hybrid disk arrays

Abstract

Flash-memory based solid state disks, though currently more expensive and inadequate in write cycles, offer much faster read accesses while consume much less energy compared with hard disk drives. In order to gain complementary merits of hard disks and flash disks, we propose a hybrid disk array based storage architecture for data-intensive server-class applications. Further, on top of the proposed storage architecture, a self- adaptive f ile rea llocation strategy, called SAIL, which is able to adapt to dynamically changed file access patterns, is developed. Comprehensive trace-driven experiments demonstrate that compared with a very recent file placement technique PB-PDC, which also employs the combined advantages of a hard disk and a flash memory device, SAIL exhibits its strength in both performance and energy consumption while maintains the reliability of flash disks by confining their write cycles. © 2008 Springer Berlin Heidelberg.