摘要
由于NVM器件集成度和DIMM接口数量的限制,大容量SCM系统中必然包含DIMM接口和PCIe接口NVM存储设备.这2类NVM存储设备在访问接口、访问方式、I/O性能、存储容量和内嵌处理能力等方面存在很大差异,这使得现有的内存和外存均难以直接应用与统一管理2类NVM存储设备;同时不同文件、文件数据与元数据、文件内各部分数据之间的访问特性和管理要求也不相同,这给高效管理大容量SCM系统带来了极大的挑战.提出了面向SCM的聚合文件系统SCMPFS,统一管理2类NVM存储设备.首先给出了聚合文件系统的结构;接着给出了元数据分层管理算法,具有元数据属性和NVM存储设备的特性,重构元数据的组织结构,将元数据属性合理分布到2类NVM存储设备中,提高元数据查找速度和管理效率;设计了数据聚合管理算法,通过打破文件数据的单一组织结构、通过文件数据在2类NVM存储设备之间的合理分布,提高访问文件的响应速度和文件系统的I/O性能,有效利用2类NVM存储设备中的存储容量;最后使用ramfs和PMBD分别模拟DIMM接口和PCIe接口NVM存储设备,在FUSE的基础上实现了SCMPFS的原型,使用postmark和Linux内核源码进行了测试与分析,验证了SCMPFS相比PMBD上Ext3能提高30%~63%的I/O性能,接近与PMFS,同时避免DIMM接口NVM存储设备容量的限制;此外测试也表明软件和接口开销成为影响大容量SCM系统性能的重要因素之一.
Due to the limitation of integration of NVM and the number of DIMM interface,DIMM and PCIe interface NVM devices should coexist in the massive SCM.But they have many differences such as interface,access granularity,I/O performance,storage capacity and embedded processing capability.Therefore,the existing main memory and file management algorithms cannot be applied in massive SCM management directly.At the same time,there are also many differences among files,attributes and data portions in file.Therefore,managing two types of NVM devices uniformly and efficiently in massive SCM is very challenging.In this paper,we present a polymerization file system for SCM named as SCMPFS,aiming at implementing massive SCM system with two types of NVM devices.Firstly,the hierarchical metadata management algorithm is given to decompose and distribute metadata between two types of NVM devices,and meet the characteristics of different attributes and NVM devices.It can improve the efficiency of file search and attribute access of massive SCM system.Secondly,apolymerization data management algorithm is provided.It can alleviate the storage capacity limitation of DIMM interface NVM device compared with some new file systems for byteaddressable NVM device,meanwhile it can improve I/O performance of the file system compared with those popular ones on block interface NVM device.It reorganizes data of file and integrates two types of NVM devices to store and manage data of file.At last,the prototype of SCMPFS is implemented and evaluated by postmark and copying Linux kernel source.The results verify that SCMPFS improves about from 30% to 63% I/O performance compared with Ext3 on PMBD,and obtains the similar I/O performance with PMFS.At the same time,it can rational manage the storage capacity of two types NVM devices to alleviate the storage capacity limitation of DIMM interface NVM device.The results also show that software and interface overhead become one main factor for the efficiency of massive SCM.
出处
《计算机研究与发展》
EI
CSCD
北大核心
2015年第S2期18-28,共11页
Journal of Computer Research and Development
基金
国家自然科学基金项目(61300228)
江苏省自然科学基金项目(BK20140570)
江苏省科技支撑项目(BE2013103)
浙江省自然科学基金项目(LY13F020012)
深圳市科技计划项目(JCYJ20130401095947222)
关键词
存储级内存
非易失存储器
文件系统
元数据
混合存储系统
storage class memory
non-volatile memory(NVM)
file system
metadata
hybrid storage system
