APMSS:一种具有非对称接口的固态存储系统

APMSS:The New Solid Storage System with Asymmetric Interface

固态存储系统是解决计算机系统存储墙问题的重要手段,但当前所常用的基于数据块访问方式有很大的局限,存在写放大和无法利用内部存储器件支持字节读写特性等问题,严重影响了固态存储系统的I?O性能和使用寿命.设计了具有非对称接口的固态存储系统(APMSS).在分解文件系统层所提交访问请求的基础上,针对读操作的特性,设计了基于块的读机制,避免改变读粒度增加I?O软件栈开销,并能发挥读缓存的作用;设计了最小化直接写机制,包含通用块层的多粒度固态存储系统映射算法和驱动层的动态粒度写算法,仅将实际需写入数据和位置等信息发送给固态存储系统,提高固态存储系统的写性能,并减少对固态存储系统使用寿命的影响.在开源的块接口固态存储系统PMBD的基础上实现了APMSS的原型,使用存储系统的通用测试工具Fio和Filebench进行测试,结果表明APMSS上的Ext4相比PMBD上的Ext2和Ext4能提高9.6%～29.8%的写性能.

The solid storage system is an important way to solve the problem of computer memory wall. But the existing block-based storage management strategy can’t use the advantages of byte-addressable characteristics in solid storage system and causes write amplification, which seriously reduces the I/O performance and lifetime of NVM devices. In term of this problem, the new solid storage system with asymmetric interface named APMSS is presented, and the management of read and write access request are separated by the analysis of two type access request. The read access request is still managed by block unit to avoid increasing the overhead of I/O stack and keep high performance by cache. The minimized direct write strategy is designed and the write access request is managed by dynamic granularity to reduce the communication and written data to solid storage system. At the same time, the multi-granularity mapping algorithm is designed to avoid exchanging amplification between memory and solid storage system and improve the I/O performance. Then the write amplification of solid storage system could be avoided and the write performance of NVM devices could be improved. The prototype is implemented based on PMBD which is the open source solid storage system simulator. Fio and Filebench are used to test the read and write performance of Ext2 on PMBD, Ext4 on PMBD and Ext4 on APMSS. The test results show that Ext4 on APMSS can improve sequential write performance by 9.6%~29.8% compared with Ext2 and Ext4 on PMBD.