I/O Scheduling Algorithm for Data Servers in Cloud Storage Environments
-
摘要: 在云存储系统的体系架构中，当前对数据服务器守护进程的I/O请求调度采用先来先服务（first in first out）策略，这种调度策略没有考虑不同类型I/O请求的时效性要求，容易造成时效性要求高的I/O请求因被阻塞而无法得到及时处理，从而降低整个系统的服务质量.为解决该问题，本文提出一种用于云存储数据服务器的I/O请求调度算法.该算法首先对来自客户端的I/O请求进行分类，并赋予不同的优先级；然后以合适的时长作为周期、以分时间片的方式对不同优先级的I/O请求进行周期性的调度.分布式文件系统仿真实验结果表明，该算法在重负载情况下对实时请求的响应速度提高了20%，同时也兼顾了低优先级请求的响应性能.Abstract: Distributed file systems (DFSs) are generally employed for storing user data while designing a cloud storage system. The primary aspects of DFSs include efficient storage and management of metadata, data distribution strategies, and reliability of user data. In the case of data servers of a DFS, the FIFO (first in first out) strategy is adopted for scheduling I/O requests which are received by a data server daemon. The FIFO algorithm prioritises all such requests equally; requests that require better quality of services may therefore be blocked for long durations. To address this issue, a new priority based periodic scheduling algorithm (PPSA) has been proposed. Initially, PPSA classifies requests into different priority queues. Then, it periodically schedules requests according to their respective priorities and dedicated time slices. The obtained DFS simulation results show that PPSA can increase the response performance of heavy-load real-time requests by 20%, and can also ascertain the lowest response time performance for other requests.
-
Key words:
- big data /
- cloud computing /
- distributed file system /
- periodic /
- priority /
- scheduling algorithms
-
图 4 不同调度策略的系统响应时间比较
Figure 4. Comparison of system response times for different scheduling policies
表 1 t0类请求流数目对系统响应性能的影响
Table 1. Effect of the number of class t0 request flows on the system response performance
t0类请求
流数量/个FIFO 优先级调度 PPSA t0 t1 t2 t0 t1 t2 t0 t1 t2 20 2.92 2.96 2.95 1.82 2.39 3.82 1.83 2.42 3.82 40 2.97 2.97 2.98 1.90 2.72 4.22 1.92 2.73 4.25 60 2.95 2.95 2.99 2.02 3.12 4.63 2.05 3.12 4.61 80 2.93 2.96 2.91 2.20 3.62 4.94 2.15 3.47 4.70 100 2.99 2.97 2.93 2.31 4.02 ∞ 2.12 3.47 4.73 
下载: 导出CSV
表 2 t1类请求流数目对系统响应性能的影响
Table 2. Effect of the number of class t1 request flows on the system response performance
t1类请求
流数量/个FIFO 优先级调度 PPSA t0 t1 t2 t0 t1 t2 t0 t1 t2 50 2.66 2.66 2.65 1.99 2.68 3.32 2.02 2.72 3.28 100 2.96 2.98 2.97 2.17 3.09 4.10 2.12 3.00 3.97 150 3.02 2.99 2.98 2.19 3.36 4.54 2.15 3.21 4.51 200 2.98 2.98 2.99 2.17 3.57 4.93 2.13 3.42 4.76 250 2.97 2.96 2.98 2.18 3.73 ∞ 2.16 3.44 4.74
下载: 导出CSV
-
Zephoria Inc. The Top 20 valuable facebook statistics[EB/OL].(2018-04-25)[2018-06-05]. https://zephoria.com/top-15-valuable-facebook-statistics/ Dropbox Inc. Dropbox help center[EB/OL]. (2017-08-16)[2017-11-14]. https://www.dropbox.com/help. Baidu Inc. Baidu mobile platform[EB/OL]. (2017-09-15)[2017-11-14]. https://pan.baidu.com/platform/home. 腾讯公司.微云会员存储空间构成[EB/OL]. (2017-06-13)[2017-11-14]. https://www.weiyun.com/vip/capacity. Qihu360 Inc. 360 yunpan agreement[EB/OL]. (2017-03-15)[2017-11-14]. https://yunpan.360.cn/index/agreement. XTAO P, HU Z G, LTU D B, et al. Energy-efficiency enhancedvirtual machine scheduling policy for mixed workloads in cloudenvironments[J]. Computers &. Electrical Engineering, 2014, 40(5):1650-1665. http://dl.acm.org/citation.cfm?id=2644083 王健宗, 谌炎俊, 谢长生.面向云存储的I/O资源效用优化调度算法研究[J].计算机研究与发展, 2013, 50(8):1657-1666. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=jsjyjyfz201308009WANG Jianzong, CHEN Yanjun, XIE Changsheng. Research on I/O resource scheduling algorithms for utility optimization towardscloud storage[J]. Journal of Computer Research and Developmen, 2013, 50(8):1657-1666. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=jsjyjyfz201308009 郭松辉, 龚雪窑, 王炜, 等.一种动态优先级排序的虚拟机I/O调度算法[J].计算机科学, 2017, 44(1):13-19. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=jsjkx201701003GUO Songhui, GONG Xuerong, WANG Wei, et al. I/O Scheduling algorithm based on dynamic prioritization in virtual machines[J]. Computer Science, 2017, 44(1):13-19. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=jsjkx201701003 WEIL S, BRANDT S, MILLER E, et al. Ceph: a scalable, high-performance distributed file system[C]//In Proceedings of the 7th Symposium on Operating Systems Design and Implementation.[S.l.]: USENIX Association, 2006: 307-320. Red Hat, Inc. Gluster file system[EB/OL].(2017-01-21)[2017-06-05]. http://www.gluster.org/documentation/About_Gluster. Apache Software Foundation. HDFS architecture[EB/OL]. (2017-09-15)[2017-11-14]. http://hadoop.apache.org/docs/r3.0.0/hadoop-project-dist/hadoop-hdfs/HdfsDesign.html. LIU S, HUANG X, FU H, et al. Understanding data characteristics and access patterns in a cloud storage system[C]//In the 13th IEEE/ACM International Symposium on Cluster, Cloud and Grid Computing, IEEE, 2013: 327-334. KUROSE J, ROSS K. Computer networking:a top-down approach[M]. 6Ed. Hong Kong:Pearson Education Asia Limited, 2014:87-92. AHMED A, DARRELL D E L, JEHAN F P, et al. File access prediction with adjustable accuracy[C]//In Proceedings of the 21st International Conference on Performance, Computing and Communications.[S.l.]: IEEE, 2002: 131-140. ISHⅡ R P, MELLO R F D. An online data access prediction and optimization approach for distributed systems[J]. IEEE Transactions on Parallel and Distributed Systems, 2012, 23(6):1017-1029. doi: 10.1109/TPDS.2011.256 LIU Y, FIGUEIREDO R, CLAVIJO D, et al. Towards simulation of parallel file system scheduling algorithms with PFSsim[C/OL]//In Proceedings of the 7th IEEE International Workshop on Storage Network Architectures and Parallel I/O, 2011.[2017-08-12].http://storageconference.us/2011/Presentations.html. VARGA A, HORNIG R. An overview of the OMNeT++ simulation environment[C]//In Proceedings of the 1st International Conference on Simulation Tools and Techniques for Communications, Networks and Systems & Workshops.[S.l.]: ICST, 2008: 60-70. BUCY J S, SCHINDLER J, SCHLOSSER S W, et al. The disksim simulation environment version 4.0 reference manual (cmu-pdl-08-101)[R]. Pittsburgh: Carnegie Mellon University Parallel Data Laboratory, 2008. -
下载:
点击查看大图
图(4) / 表(2)
计量
- 文章访问数: 424
- HTML全文浏览量: 147
- PDF下载量: 77
- 被引次数: 0