我们知道压力测试的软件确实很多，诸如微软的WAST，惠普的LoadRunner以及等等其他的，但这些软件学习起来还是需要花费些时间，在选择上实在头痛，后来在郭欣的那本《构建高性能Web站点》【PDF下载 http://www.linuxidc.com/Linux/2015-02/113430.htm】上看到了他介绍的这款Apache自带的压力测试工具AB，十分喜爱，于是今天终于有机会体验下ab对网站的压力测试。
实验之前我的apache已经安装了，操作系统：Ubuntu 10.04 VMware 7.0
1、先查看一下版本信息 ab -V（注意是大写的V） 01.linuxidc@linuxidc:~$ ab -V 02.This is ApacheBench, Version 2.3 <$Revision: 655654 $> 03.Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/ 04.Licensed to The Apache Software Foundation, http://www.apache.org/
2、我们也可以使用小写的v查看下ab命令的一些属性 ab -v 01.linuxidc@linuxidc:~$ ab -v 02.ab: option requires an argument -- v 03.ab: wrong number of arguments 04.Usage: ab [options] [http[s]://]hostname[:port]/path 05.Options are: 06. -n requests Number of requests to perform 07. -c concurrency Number of multiple requests to make 08. -t timelimit Seconds to max. wait for responses 09. -b windowsize Size of TCP send/receive buffer, in bytes 10. -p postfile File containing data to POST. Remember also to set -T 11. -u putfile File containing data to PUT. Remember also to set -T 12. -T content-type Content-type header for POSTing, eg. 13. 'application/x-www-form-urlencoded' 14. Default is 'text/plain' 15. -v verbosity How much troubleshooting info to print 16. -w Print out results in HTML tables 17. -i Use HEAD instead of GET 18. -x attributes String to insert as table attributes 19. -y attributes String to insert as tr attributes 20. -z attributes String to insert as td or th attributes 21. -C attribute Add cookie, eg. 'Apache=1234. (repeatable) 22. -H attribute Add Arbitrary header line, eg. 'Accept-Encoding: gzip' 23. Inserted after all normal header lines. (repeatable) 24. -A attribute Add Basic WWW Authentication, the attributes 25. are a colon separated username and password. 26. -P attribute Add Basic Proxy Authentication, the attributes 27. are a colon separated username and password. 28. -X proxy:port Proxyserver and port number to use 29. -V Print version number and exit 30. -k Use HTTP KeepAlive feature 31. -d Do not show percentiles served table. 32. -S Do not show confidence estimators and warnings. 33. -g filename Output collected data to gnuplot format file. 34. -e filename Output CSV file with percentages served 35. -r Don't exit on socket receive errors. 36. -h Display usage information (this message) 37. -Z ciphersuite Specify SSL/TLS cipher suite (See openssl ciphers) 38. -f protocol Specify SSL/TLS protocol (SSL2, SSL3, TLS1, or ALL)
3、现在我们就对88181的网站进行一次压力测试吧，使用命令ab -n1000 -c10 http://www.88181.com/index.php，其中 -n1000 表示总请求数 -c10表示并发用户数为10 http://www.88181.com/index.php 表示请求的URL，下面是测试的结果，其中我们最关心的三个指标，我已经注释出来了。
01.linuxidc@linuxidc:~$ ab -n1000 -c10 http://www.88181.com/index.php 02.This is ApacheBench, Version 2.3 <$Revision: 655654 $> 03.Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/ 04.Licensed to The Apache Software Foundation, http://www.apache.org/ 05. 06. 07.Benchmarking www.88181.com (be patient) 08.Completed 100 requests 09.Completed 200 requests 10.Completed 300 requests 11.Completed 400 requests 12.Completed 500 requests 13.Completed 600 requests 14.Completed 700 requests 15.Completed 800 requests 16.Completed 900 requests 17.Completed 1000 requests 18.Finished 1000 requests 19. 20. /*WEB服务器用的是nginx*/ 21.Server Software: nginx 22.Server Hostname: www.88181.com 23.Server Port: 80 24. 25.Document Path: /index.php 26.Document Length: 154 bytes 27. 28.Concurrency Level: 10 29.Time taken for tests: 74.373 seconds 30.Complete requests: 1000 31.Failed requests: 0 32.Write errors: 0 33.Non-2xx responses: 1000 34.Total transferred: 330000 bytes 35.HTML transferred: 154000 bytes 36./*大家最关心的指标之一，指的是吞吐率 37.相当于 LR 中的 每秒事务数 ，后面括号中的 mean 表示这是一个平均值*/ 38.Requests per second: 13.45 [#/sec] (mean) 39./*大家最关心的指标之二，指的是用户平均请求等待时间 40.相当于 LR 中的 平均事务响应时间 ，后面括号中的 mean 表示这是一个平均值*/ 41.Time per request: 743.726 [ms] (mean) 42./*大家最关心的指标之三，指的是服务器平均请求处理时间 43.Time per request: 74.373 [ms] (mean, across all concurrent requests) 44.Transfer rate: 4.33 [Kbytes/sec] received 45. 46.Connection Times (ms) 47. min mean[ /-sd] median max 48.Connect: 129 163 245.3 145 3154 49.Processing: 129 576 1510.8 147 11756 50.Waiting: 129 567 1502.0 147 11756 51.Total: 261 739 1543.7 294 11888 52. 53.Percentage of the requests served within a certain time (ms) 54. 50% 294 55. 66% 297 56. 75% 304 57. 80% 308 58. 90% 1290 59. 95% 3452 60. 98% 7582 61. 99% 7962 62. 100% 11888 (longest request)
4、为了使结果更有对比性，我们将并发用户更改为100个进行压力测试，我这里只将三个指标贴出来。 01.Requests per second: 190.95 [#/sec] (mean) 02.Time per request: 523.694 [ms] (mean) 03.Time per request: 5.237 [ms] (mean, across all concurrent requests)
5、将并发用户改为200个进行测试 01.Requests per second: 186.00 [#/sec] (mean) 02.Time per request: 1149.433 [ms] (mean) 03.Time per request: 5.747 [ms] (mean, across all concurrent requests)
6、500个并发用户时的情况 01.Requests per second: 180.99 [#/sec] (mean) 02.Time per request: 2631.662 [ms] (mean) 03.Time per request: 5.263 [ms] (mean, across all concurrent requests)
我们来分析下测试的结果，先对比下吞吐率，当并发用户的时候吞吐率最高为190 reqs/s,当并发用户数为200,500 吞吐率下降了，随之用户的等待时间更是明显增加了，已经有2s的等待时间了。这说明性能明显下降了。当然分析这个测试结果并不是说明88181的网站的并发用户只能在500左右，因为我是在服务器负荷的情况下就行测试的，这显然不能说明问题。另外我们在生产环境下测试的时候，最好能将测试结果做成报表，这样可以非常清晰地对比出问题来，好了，我该准备下，给上面提交一份我们公司网站的测试报告了。
