一种基于PCM的文件系统设计与实现

发布时间：2018-05-28 23:45

本文选题：相变存储器 + 文件系统　；参考：《华中科技大学》2013年硕士论文

【摘要】：相变存储器（Phase Change Memory, PCM）作为一种新型的非易失性存储介质，具有高存取速度、非易失性、可按字节寻址等特性。PCM利用特殊材料在晶态和非晶态的电阻差异来记录信息，具有和DRAM同一数量级的读写速度。传统文件系统都针对磁盘等特性设计的，直接应用在PCM上还存在很多问题，不仅存在空间浪费，还会损失部分PCM的性能。针对PCM特性设计新的文件系统已经成为了当前学术界的研究热点。针对PCM设计了一种专用文件系统PCMFS，能够充分利用PCM读延迟低的特点，并考虑单位存储成本，提高存储利用率。PCMFS能够直接支持虚拟文件系统接口，采用inode等数据结构，简化了元数据的操作，从而减少元数据管理开销；PCMFS将索引节点表和数据区整合为了一个物理区域，并且采用了两边向中间分配的方式，，这样就可以适应不同应用场景对于索引节点和数据块的数量要求；PCMFS还设计了DIT（被删除索引节点表）来处理被删除的索引节点，减少数据空洞；PCMFS还引入了数据迁移的机制，为了在应用场景发生突变的时候保证空间利用率。最后在上述设计方案的基础上，在linux平台上实现PCMFS原型。经过ext2（在ramdisk工具上运行）、ramfs、tmpfs和PCMFS的对比测试，PCMFS在空间使用率上要比ext2高12%，平均访问速度比ext2高23.3%，比ramfs和tmpfs低4.5%。由于ramfs和tmpfs本身就是针对内存优化的文件系统，因此本设计方案表现出较好的性能，并且在空间节省上也具有优势。
[Abstract]:Phase change memory Phase Change Memory, PCM), as a new non-volatile storage medium, has the characteristics of high access speed, non-volatile, and can be addressed by bytes. PCMs record information by using the resistance difference between crystalline and amorphous states of special materials. Has the same reading and writing speed as DRAM. Traditional file systems are designed for disk and other characteristics. There are still many problems in the direct application of PCM, which not only waste space, but also lose part of the performance of PCM. Designing a new file system for PCM features has become a hot research topic in academic circles. A special file system (PCMFSs) is designed for PCM, which can take full advantage of the low read delay of PCM, consider the unit storage cost, improve storage utilization. PCMFS can directly support the virtual file system interface, and adopt the data structure such as inode, etc. It simplifies the operation of metadata, thus reducing the metadata management overhead. PCMFS integrates the index node table and data area into a physical area, and distributes them to the middle of each other. In this way, PCMFS can meet the requirements of different application scenarios for the number of index nodes and data blocks. The PCMFS also designs a DIT (deleted index node table) to deal with the deleted index nodes, and reduces the data void. PCMFS also introduces a mechanism of data migration. In order to ensure the space utilization rate when the application scene changes. Finally, on the basis of the above design scheme, PCMFS prototype is implemented on linux platform. After a comparative test of running tmpfs and PCMFS on the ramdisk tool, the space utilization rate of PCMFS is 12% higher than that of ext2, the average access speed is 23. 3% higher than that of ext2, and 4.5% lower than that of ramfs and tmpfs. Because ramfs and tmpfs are file systems for memory optimization, this design has good performance and advantages in space saving.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TP333

【共引文献】