计算机科学 ›› 2017, Vol. 44 ›› Issue (6): 43-50.doi: 10.11896/j.issn.1002-137X.2017.06.007

• 2016 年全国信息存储技术学术年会 • 上一篇    下一篇

一种基于热数据识别技术的UBIFS优化方案

马骏,童薇,刘景宁,刘景超   

  1. 华中科技大学光电国家实验室 武汉430074,华中科技大学光电国家实验室 武汉430074;华中科技大学计算机科学与技术学院 武汉430074,华中科技大学光电国家实验室 武汉430074;华中科技大学计算机科学与技术学院 武汉430074,华中科技大学光电国家实验室 武汉430074
  • 出版日期:2018-11-13 发布日期:2018-11-13
  • 基金资助:
    本文受国家863项目计划(2015AA016701,5AA015301),国家自然科学基金资助

Optimization Scheme of UBIFS Based on Hot Data Identification Technology

MA Jun, TONG Wei, LIU Jing-ning and LIU Jing-chao   

  • Online:2018-11-13 Published:2018-11-13

摘要: NAND Flash介质具有特殊的物理性质,传统文件系统不能直接对NAND Flash进行管理,容易造成NAND Flash设备性能下降、磨损不均衡等负面影响。闪存文件系统将FTL与文件系统功能有机地结合起来,可更好地发挥NAND Flash的高性能。无序区块镜像文件系统(Unsorted Block Image File System,UBIFS)是一种被广泛使用的闪存文件系统,但其存在着写放大和垃圾回收操作频繁触发等问题。针对UBIFS中存在的问题,提出利用多哈希函数的哈希表对热数据进行识别,以降低热数据识别开销,提高热数据识别的准确率;采用多日志技术,将不同热度的日志、数据分开存放,以减少垃圾回收触发频率;采用热数据日志延迟提交技术来减少UBIFS中日志提交带来的元数据修改,进而减少了写放大产生的次数。测试与分析表明, 与原UBIFS相比,优化后的UBIFS的系统内部写物理块的次数减少5%~10%,垃圾回收操作触发的次数减少了7%~13%,同时系统的IOPS提高了5%~18%,系统性能下降现象得到了有效缓解。

关键词: 闪存,UBIFS文件系统,热数据,垃圾回收

Abstract: NAND Flash memory can’t be managed by traditional file systems for its special access characteristics.Although the problem is solved by using FTL in NAND Flash devices,the structure and algorithm in traditional file systems designed for disk can easily cause severe performance degradation and uneven wear in NAND Flash devices.Flash file systems that combine some FTL functions can make better use of NAND Flash memory with further optimization.UBIFS is a widely used Flash file system in Linux,but there are still severe write-amplification and frequent garbage collection in the storage system using UBIFS.In order to solve these problems of UBIFS,this research used hash table with multi-hash functions to identify hot data in UBIFS to reduce identification overhead and improve recognition accuracy.By using multiple log,cold and hot data are separated into different storage area to reduce the frequency of garbage collection.The delay commit technology of log was also adopted to reduce the number of times write-amplification occurs caused by frequent log commit.A series of experiments were conducted to verify the performance of the proposed method.Experiments show that internal writes to physical block in optimized UBIFS are reduced by 5%~10% compared to that in the original UBIFS,and the times of garbage collection triggered in optimized UBIFS were reduced by 7%~13% compared to that in the original UBIFS.In general,IOPS of storage system is improved by 5%~18% and system performance degradation is effectively alleviated by using optimized UBIFS.

Key words: NAND flash,UBIFS,Hot data,Garbage collection

[1] LU Y Y L,SHU J W,WANG W.ReconFS:A Reconstructable File System on NAND Flash Storage[C]∥Proceedings of the Usenix Conference on File & Storage Technologies.2014:75-88.
[2] ROSENBLUM M,OUSTERHOUT J K.The design and implementation of a log-structured file system[J].ACM Transactions on Computer Systems,1992,10(1):26-52.
[3] LEE C,SIM D,HWANG J Y,et al.F2FS:A New File System for NAND Flash Storage[C]∥Proceedings of the Usenix Conference on File & Storage Technologies(FAST).2015.
[4] QUICK D,ALZAABI M.Forensic Analysis of the Android File System Yaffs2[C]∥9th Australian Digital Forensics Conference.2011.
[5] BITYUTSKIY A B.JFFS3 design issues.http://www.linux-mtd.infradead.org.
[6] OH Y,KIM E,CHOI J,et al.Optimizations of LFS with slack space recycling and lazy indirect block update[C]∥Proceedings of the Annual Haifa Experimental Systems Conference.2010.
[7] KANG D.Enhanced UBI layer for fast boot-up times of mobile consumer devices[J].IEEE Transactions on Consumer Electro-nics,2012,8(2):450-454.
[8] LU Y,SHU J,ZHENG W.Extending the lifetime of NANDFlash-based storage through reducing write amplification from file systems[C]∥Proceedings of the USENIX Conference on File and Storage Technologies (FAST).2013:257-270.
[9] NARAYANAN D,HODSON O.Whole-system persistence[C]∥Proceedings of the 17th International Conference on ArchitecturalSupport for Programming Languages and Operating Systems.New York,USA,2012:401-410.
[10] JOO Y,NIU D,DONG X,et al.Energy-and endurance-awaredesign of phase change memory Caches[C]∥Proceedings of the Conference on Design,Automation and Test in Europe.Leuven,Belgium,2010:136-141.
[11] LUOJIE X,KURKOSKI B M.An improved analytic expression for write amplification in NAND Flash[C]∥2012 International Conference on Computing,Networking and Communications (ICNC).IEEE,2012:497-501.
[12] CAULFIELD A M,DE A,COBURN J,et al.Moneta:A high-performance storage array architecture for next-generation,non-volatile memories[C]∥Proceedings of the 2010 43rd Annual IEEE/ACM International Symposium on Microarchitecture.2010:385-395.
[13] HSIEH J W,KUO T W,CHANG L P.Efficient identification of hot data for NAND Flash memory storage systems[J].ACM Transactions on Storage (TOS),2006,2(1):22-40.
[14] DHIMAN G,AYOUB R,ROSING T.PDRAM:a hybrid PRAM and DRAM main memory system[C]∥Design Automation Conference.2009:664-669.
[15] SHI Z,CHEN X L,JI J S,et al.Space Efficient Mapping Management for Large-scale NAND Flash File System[J].Journal of Chinese Computer Systems,2010,1(1):155-159.(in Chinese) 时正,陈香兰,纪金松,等.大容量NAND Flash文件系统中的地址映射算法研究[J].小型微型计算机系统,2010,31(1):155-159.
[16] GUPTA A,KIM Y,URGAONKAR B.DFTL:a NAND Flash translation layer employing demand-based selective caching of page-level address mappings[J].ACM Sigarch Computer Architecture News, 2009,37(1):229-240.
[17] PARK D,DEBNATH B,DU D.CFTL:a convertible NANDFlash translation layer adaptive to data access patterns[J].ACM SIGMETRICS Performance Evaluation Review,2010,38(1):365-366.
[18] LU Y Y,SHU J W,ZHENG W M.Extending the lifetime ofNAND Flash-based storage through reducing write amplification from file systems[C]∥Proceedings of the 11th USENIX Conference on File and Storage Technologies (FAST’13).2013.
[19] LEE H,YUN H,LEE D.HFTL:hybrid NAND Flash translation layer based on hot data identification for NAND Flash memory[J].IEEE Transactions on Consumer Electronics,2009,55(4):2005-2011.
[20] CHEN F,LUO T,ZHANG X.CAFTL:A content-aware NAND Flash translation layer enhancing the lifespan of NAND Flash memory based solid state drives[C]∥Proceedings of the 9th USENIX Conference on File and Stroage Technologies.USENIX Association,2011: 6.
[21] LEE S,PARK D,CHUNG T,et al.A Log Buffer based NAND Flash Translation Layer Using Fully Associative Sector Translation[J].IEEE Transactions on Embedded Computing Systems,2007,6(3):1539-9087.
[22] CHUNG T,PARK D,PARK S,et al.System Software forNAND Flash Memory:A Survey[C]∥Proceedings of the International Conference on Embedded and Ubiquitous Computing.2006:394-404.
[23] KAWAGUCHI A,NISHIOKA S,MOTODA H.A NAND Fla-sh-Memory Based File System[C]∥ 1995 USENIX Technical Conference.1995:155-164.
[24] CHIANG M L,CHANG R C.Cleaning Policies in Mobile Com-puters Using NAND Flash Memory[J].Journal of System and Software,1999,48(3):213-231.
[25] KIM H J,LEE S G.A New NAND Flash Memory Management for NAND Flash Storage System[C]∥Proceedings of the 23rd International Computer Software and Applications Conference.1999:284.
[26] CHIANG M,CHENG C,WU C.A new FTL-based NANDFlash memory management scheme with fast cleaning mecha-nism[C]∥International Conference on Embedded Software and Systems,2008(ICESS’08).IEEE,2008:205-214.
[27] PARK D,Du D H C.Hot data identification for flash-basedstorage systems using multiple bloom filters[C]∥MASS Storage Systems and Technologies.IEEE,2011:1-11.
[28] PARK D,Debnath B,Nam Y,et al.HotDataTrap:a sampling-based hot data identification scheme for flash memory[C]∥Proceedings of the 27th Annual ACM Symposium on Applied Computing.ACM,2012:759-767.
[29] MTD.MemoryTechnology Device.http://www.Linux-mtd.infradead.org.
[30] WANG C,WONG W.Extending the lifetime of NAND Flashmemory by salvaging bad blocks[C]∥Design,Automation & Test in Europe Conference & Exhibition (DATE).IEEE,2012.
[31] JUNG H,YOON K,SHIM H,et al.LIRS-WSR:Integration of LIRS and Writes Sequence Reordering for Flash Memory[J].IEEE Transactions on Consumer Electronics,2008,4(3):1215-1223.
[32] JO H,KAMG J U,PARK S Y,et al.FAB:flash-aware buffer management policy for portable media players[J].IEEE Transactions on Consumer Electronics,2006,2(2):485-493.
[33] KIM H,AHN S.BPLRU:a buffer management scheme for improving random writes in NAND Flash storage[C]∥USENIX Association.2008:1-14.
[34] OU Y,HRDER T,JIN P.CFDC:a NAND Flash-aware replacement policy for database buffer management[C]∥ ACM.2009:15-20.
[35] PARK S,et al.CFLRU:a replacement algorithm for NANDFlash memory[C]∥ACM.2006:234-241.
[36] KIM J,SHIM H,PARK S Y,et al.NAND FlashLight:a lightweight NAND Flash file system for embedded systems[J].ACM Transactions on Embedded Computing Systems (TECS),2012,1(1):18.
[37] SIMMONDS C.Linux NAND Flash file systems JFFS2 vs UBIFS[C]∥Embedded Systems Conference UK.2009.
[38] HAN C X,CHEN X L,XI L I,et al.Impact of UBIFS Wear-leveling on System I/O Performance[J].Computer Engineering,2009,5(6):260-262.
[39] BROWN N.JFFS2,UBIFS,and the growth of NAND Flash storage[EB/OL].https://lwn.net/Articles/528617.
[40] KANG E,JACKSON D.Formal modeling and analysis of aNAND Flash filesystem in Alloy[M]∥Abstract state machines,B and Z.Springer Berlin Heidelberg,2008:294-308.

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