A performance model and file system space allocation scheme for SSDs

Abstract

Solid State Drives (SSDs) are now becoming a part of main stream computers. Even though disk scheduling algorithms and file systems of today have been optimized to exploit the characteristics of hard drives, relatively little attention has been paid to model and exploit the characteristics of SSDs. In this paper, we consider the use of SSDs from the file system standpoint. To do so, we derive a performance model for the SSDs. Based on this model, we devise a file system space allocation scheme, which we call Greedy-Space, for block or hybrid mapping SSDs. From the Postmark benchmark results, we observe substantial performance improvements when employing the Greedy-Space scheme in ext3 and Reiser file systems running on three SSDs available in the market.