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》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）

studiogang@studiogang:~$ ab -V This is ApacheBench, Version 2.3 <$Revision: 655654 $> Copyright 1996 Adam Twiss, Zeus Technology Ltd, http:///index.php This is ApacheBench, Version 2.3 <$Revision: 655654 $> Copyright 1996 Adam Twiss, Zeus Technology Ltd, http:// (be patient) Completed 100 requests Completed 200 requests Completed 300 requests Completed 400 requests Completed 500 requests Completed 600 requests Completed 700 requests Completed 800 requests Completed 900 requests Completed 1000 requests Finished 1000 requests Server Software: nginx Server Hostname: Server Port: 80 Document Path: /index.php Document Length: 154 bytes Concurrency Level: 10 Time taken for tests: 74.373 seconds Complete requests: 1000 Failed requests: 0 Write errors: 0 Non-2xx responses: 1000 Total transferred: 330000 bytes HTML transferred: 154000 bytes Requests per second: 13.45 [#/sec] (mean) Time per request: 743.726 [ms] (mean) /*大家最关心的指标之三，指的是服务器平均请求处理时间Time per request: 74.373 [ms] (mean, across all concurrent requests) Transfer rate: 4.33 [Kbytes/sec] received Connection Times (ms) min mean[+/-sd] median max Connect: 129 163 245.3 145 3154 Processing: 129 576 1510.8 147 11756 Waiting: 129 567 1502.0 147 11756 Total: 261 739 1543.7 294 11888 Percentage of the requests served within a certain time (ms) 50% 294 66% 297 75% 304 80% 308 90% 1290 95% 3452 98% 7582 99% 7962 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。

Requests per second: 190.95 [#/sec] (mean) Time per request: 523.694 [ms] (mean) 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

Requests per second: 186.00 [#/sec] (mean) Time per request: 1149.433 [ms] (mean) Time per request: 5.747 [ms] (mean, across all concurrent requests)

6、500个并发用户时的情况

Requests per second: 180.99 [#/sec] (mean) Time per request: 2631.662 [ms] (mean) 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51CTO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。