臺灣博碩士論文加值系統

隨著全球資訊網的蓬勃發展，越多的人瀏覽全球資訊網上的網頁，因而在網際網路間造成的流量越大，大量的流量會造成網路的壅塞而使的使用者上網的等待時間增加。面對這個問題我們常用proxy cache來解決。 Proxy cache可以同時減少網路上的流量並降低使用者的等待時間。 然而隨著網路流量的繼續成長，proxy cache反而因為無法處理過量的request反而造成使用者更長的等待時間。本篇論文便是以改進proxy效能的瓶頸為主， 我們提出了一個有效率的磁碟管理方法ESP (Efficient Storage management strategy for Proxies)，並且修改了squid的程式碼來實作ESP， 以使其能夠減少檔案系統的處理並降低硬碟讀寫頭的移動以提升proxy效能，經過我們修改的squid效能較原本提升了一倍。

With the enormous growth of the WWW, the Internet has seen a large volume of traffic which introduces severe congestion and worsens our surfing experience. Proxy cache is a common solution to this problem. It reduces the traffic on the Internet and the response time. However with the potential growth of the WWW, the proxy is overburdened and that in turn increases the response time even more.
In this thesis we propose an effcient mechanism ESP (Efficient Storage management policy for Proxies) to reduce the file operation and disk seek time in order to improve the performance of Squid. ESP shows a 100% performance improvement to the original squid.

第一章 簡介 7
第二章 背景知識 11
2.1階層式的Proxy 11
2.2 ICP (Internet Cache Protocol) 12
2.3 Squid 12
2.4 Web Polygraph 15
第三章 相關研究 18
3.1置換策略 18
3.2 Streaming Media Proxy 20
3.3 DISK I/O 21
第四章 實作與效能 23
4.1 實作 24
4.1.1 Buddy System 24
4.1.2 Multileveled Bitmap 27
4.1.3 置換策略 31
4.2 模擬 33
4.2.1 環境設定: 33
4.2.2 Benchmark for squid 34
4.2.3 Benchmark for ESP 35
4.2.4 ESP與squid的比較 36
4.2.5 在不同 Threshold時的比較 38
第五章 結論以及未來展望 39
5.1 結論 39
5.2 未來展望 39
Reference 41

1. http://www.hot.net.tw/magazine/online/web.txt
2. S. Floyd, ”Difficulties in simulating the Internet” in IEEE/ACM Transactions on Networking, Vol. 9, No. 4, pp.392-403, August 2001.
3. http://www.web-polygraph.org
4. http://polygraph.ircache.net/doc/papers/paper01.ps.gz
5. http://www.mindcraft.com
6. http://www.etestinglabs.com
7. M. Abrams, C. R. Standbridge. “Caching proxies: limitations and potentials.” WWW-4, Boston, December, 1995.
8. M. Arlitt, R. Friedrich and T. Jin, “Performance Evaluation of Web Proxy Cache Replacement Policies”, Performance Tools ‘98, Palma de Mallora, Spain, Available as HPL Technical Report HPL- 98- 97. September 1998.
9. P. Cao and S. Irani. “Cost-Aware WWW Proxy Caching Algorithms.” In Proc. of the USENIX Symposium on Internet Technologies and Systems, 1997.
10. S. Williams, M. Abrams, C.R. Standbridge, G.Abdulla and E.A. Fox. “Removal Policies in Network Caches for World-Wide Web Documents.” In Proceedings of the ACM Sigcomm96, Stanford University, August 1996.
11. R. Wooster and M. Abrams. “Proxy Caching that Estimates Page Load Delays.” In the 6th International World Wide Web Conference, April 7- 11, 1997.
12. P. Lorenzetti, L. Rizzo and L. Vicisano. “Replacement Policies for a Proxy Cache.” IEEE/ACM Transactions on Networking, Vol. 8, No. 2, April 2000.
13. K. L. Wu, P. S. Yu, and J. L. Wolf. “Segment-Based Proxy Caching of Multimedia Streams.” In Proceedings of the Tenth International World Wide Web Conference, Hong Kong , May 2001.
14. A. Rousskov and V. Soloviev. “On Performance of Caching Proxies.” In Proc. of the 1998 ACM SIGMETRICS Conference, 1998.
15. J. C. Mogul. “Speedier Squid: A Case Study of an Internet Server Performance problem. ” The USENIX Association Magazine, Vol. 24, No. 1:pp.50- 58, 1999.
16. E. P. Markatos, M. G.H. Katevenis, “Secondary Storage Management for Web Proxies,” The 2nd Usenix Symposium on Internet Technologies and System, Boulder, Colorado, USA Oct. 11-14, 1999.
17. T. Blackwell, J. Harris, and M. Seltzer. “Heuristic Cleaning Algorithms for Log-Structured File Systems.” In Proceedings of the 1995 Usenix Technical Conference, January 1995.
18. J. Hartman and J. Ousterhout. “The Zebra Striped Network File System.” Proc. 14-th Symposium on Operating Systems Principles, pp. 29—43, December 1993.
19. M. Nelson, B. Welch, and J. Ousterhout. “Caching in the Sprite Network File System.” ACM Transactions on Computer Systems, Vol. 6 No. 1:134—154, February 1988.
20. M. Seltzer,M.K.McKusick, K. Bostic, and C. Staelin. “An Implementation of a Log-Structured File System for UNIX”. In Proceedings of the 1995 Winter Usenix Technical Conference, San Diego, CA, January 1993.
21. E. W. Jiang. “Disk Storage Management for Internet Cache Servers.” Master Thesis, June 2001.