Performance improvement of I/O subsystems exploiting the characteristics of solid state drives

Abstract

NAND flash based Solid State Drives (SSDs) have several unique physical characteristics. Since the SSD consists of many NAND flash packages and each package is able to perform its own I/O operation, almost SSDs provide some parallel I/O operations to improve the I/O performance. Unlike hard disks, SSDs do not have data access overhead such as seek time and rotational delay as well as two operations of read and write have asymmetric performances. In this paper, we propose some techniques that could improve the I/O performance by exploiting the characteristics of SSDs. To this end, we first extract the performance parameters in SSDs such as read/write unit and erase unit. And then, the extracted performance parameters are used to configure the file system block size and I/O request size. We also present an efficient I/O scheduling scheme that fully exploits the characteristics of solid state drives: no data access overhead and asymmetric read and write performance. Through implementation on Linux operating systems, we show that the proposed schemes significantly improve the performance of I/O subsystems for solid state drives. © 2011 Springer-Verlag.