使用 ApacheBench 做網站壓力測試
ab的全稱是ApacheBench，是 Apache 附帶的一個小工具，專門用于 HTTP Server 的benchmark testing，可以同時模擬多個并發請求。前段時間看到公司的開發人員也在用它作一些測試，看起來也不錯，很簡單，也很容易使用，所以今天花一點時間看了一下。
通過下面的一個簡單的例子和注釋，相信大家可以更容易理解這個工具的使用。
一個簡單的例子
/*在這個例子的一開始，我執行了這樣一個命令 ab -n 10 -c 10 http://www.google.com/。這個命令的意思是啟動 ab ，向 www.google.com 發送10個請求(-n 10) ，并每次發送10個請求(-c 10)——也就是說一次都發過去了。跟著下面的是 ab 輸出的測試報告，紅色部分是我添加的注釋。*/
C:\Program Files\Apache Software Foundation\Apache2.2\bin>ab -n 10 -c 10 http
://www.google.com/
This is ApacheBench, Version 2.0.40-dev <$Revision: 1.146 $> apache-2.0
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Copyright 1997-2005 The Apache Software Foundation, http://www.apache.org/
Benchmarking www.google.com (be patient).....done
Server Software: GWS/2.1
Server Hostname: www.google.com
Server Port: 80
Document Path: /
Document Length: 230 bytes
Concurrency Level: 10
/*整個測試持續的時間*/
Time taken for tests: 3.234651 seconds
/*完成的請求數量*/
Complete requests: 10
/*失敗的請求數量*/
Failed requests: 0
Write errors: 0
Non-2xx responses: 10
Keep-Alive requests: 10
/*整個場景中的網絡傳輸量*/
Total transferred: 6020 bytes
/*整個場景中的HTML內容傳輸量*/
HTML transferred: 2300 bytes
/*大家最關心的指標之一，相當于 LR 中的 每秒事務數 ，后面括號中的 mean 表示這是一個平均值*/
Requests per second: 3.09 [#/sec] (mean)
/*大家最關心的指標之二，相當于 LR 中的 平均事務響應時間 ，后面括號中的 mean 表示這是一個平均值*/
Time per request: 3234.651 [ms] (mean)
/*這個還不知道是什么意思，有知道的朋友請留言，謝謝 ^_^ */
Time per request: 323.465 [ms] (mean, across all concurrent requests)
/*平均每秒網絡上的流量，可以幫助排除是否存在網絡流量過大導致響應時間延長的問題*/
Transfer rate: 1.55 [Kbytes/sec] received
/*網絡上消耗的時間的分解，各項數據的具體算法還不是很清楚*/
Connection Times (ms)
min mean[+/-sd] median max
Connect: 20 318 926.1 30 2954
Processing: 40 2160 1462.0 3034 3154
Waiting: 40 2160 1462.0 3034 3154
Total: 60 2479 1276.4 3064 3184
/*下面的內容為整個場景中所有請求的響應情況。在場景中每個請求都有一個響應時間，其中 50％ 的用戶響應時間小于 3064 毫秒，60 ％ 的用戶響應時間小于 3094 毫秒，最大的響應時間小于 3184 毫秒*/
Percentage of the requests served within a certain time (ms)
50% 3064
66% 3094
75% 3124
80% 3154
90% 3184
95% 3184
98% 3184
99% 3184
100% 3184 (longest request)
更多信息
ab 不像 LR 那么強大，但是它足夠輕便，如果只是在開發過程中想檢查一下某個模塊的響應情況，或者做一些場景比較簡單的測試，ab 還是一個不錯的選擇——至少不用花費很多時間去學習 LR 那些復雜的功能，就更別說那 License 的價格了。
下面是 ab 的詳細參數解釋，大家有興趣的可以研究一下，最近沒有足夠多的時間研究，如果哪位朋友有興趣希望可以幫忙翻譯一下每個參數的含義，有問題討論也歡迎在這里回帖 ^_^
ab [ -Aauth-username:password ] [ -cconcurrency ] [ -Ccookie-name=value ] [ -d ] [ -ecsv-file ] [ -ggnuplot-file ] [ -h ] [ -Hcustom-header ] [ -i ] [ -k ] [ -nrequests ] [ -pPOST-file ] [ -Pproxy-auth-username:password ] [ -q ] [ -s ] [ -S ] [ -ttimelimit ] [ -Tcontent-type ] [ -vverbosity] [ -V ] [ -w ] [ -x<table>-attributes ] [ -Xproxy[:port] ] [ -y<tr>-attributes ] [ -z<td>-attributes ] [http://]hostname[:port]/path
-A auth-username:password
Supply BASIC Authentication credentials to the server. The username and password are separated by a single: and sent on the wire base64 encoded. The string is sent regardless of whether the server needs it (i.e., has sent an 401 authentication needed).
-c concurrency
Number of multiple requests to perform at a time. Default is one request at a time.
-C cookie-name=value
Add a Cookie: line to the request. The argument is typically in the form of aname=value pair. This field is repeatable.
-d
Do not display the "percentage served within XX [ms] table". (legacy support).
-e csv-file
Write a Comma separated value (CSV) file which contains for each percentage (from 1% to 100%) the time (in milliseconds) it took to serve that percentage of the requests. This is usually more useful than the 'gnuplot' file; as the results are already 'binned'.
-g gnuplot-file
Write all measured values out as a 'gnuplot' or TSV (Tab separate values) file. This file can easily be imported into packages like Gnuplot, IDL, Mathematica, Igor or even Excel. The labels are on the first line of the file.
-h
Display usage information.
-H custom-header
Append extra headers to the request. The argument is typically in the form of a valid header line, containing a colon-separated field-value pair (i.e.,"Accept-Encoding: zip/zop;8bit").
-i
Do HEAD requests instead of GET.
-k
Enable the HTTP KeepAlive feature, i.e., perform multiple requests within one HTTP session. Default is no KeepAlive.
-n requests
Number of requests to perform for the benchmarking session. The default is to just perform a single request which usually leads to non-representative benchmarking results.
-p POST-file
File containing data to POST.
-P proxy-auth-username:password
Supply BASIC Authentication credentials to a proxy en-route. The username and password are separated by a single: and sent on the wire base64 encoded. The string is sent regardless of whether the proxy needs it (i.e., has sent an 407 proxy authentication needed).
-q
When processing more than 150 requests, ab outputs a progress count onstderr every 10% or 100 requests or so. The -q flag will suppress these messages.
-s
When compiled in (ab -h will show you) use the SSL protected https rather than the http protocol. This feature is experimental andvery rudimentary. You probably do not want to use it.
-S
Do not display the median and standard deviation values, nor display the warning/error messages when the average and median are more than one or two times the standard deviation apart. And default to the min/avg/max values. (legacy support).
-t timelimit
Maximum number of seconds to spend for benchmarking. This implies a -n 50000 internally. Use this to benchmark the server within a fixed total amount of time. Per default there is no timelimit.
-T content-type
Content-type header to use for POST data.
-v verbosity
Set verbosity level - 4 and above prints information on headers, 3 and above prints response codes (404, 200, etc.), 2 and above prints warnings and info.
-V
Display version number and exit.
-w
Print out results in HTML tables. Default table is two columns wide, with a white background.
-x <table>-attributes
String to use as attributes for <table>. Attributes are inserted <table here >.
-X proxy[:port]
Use a proxy server for the requests.
-y <tr>-attributes
String to use as attributes for <tr>.
-z <td>-attributes
String to use as attributes for <td>.
相關鏈接
ab 是 Apache 的一個安裝組件，所以需要下載 Apache 安裝后才能使用，可以訪問 Apache 的項目主頁來下載 http://httpd.apache.org/download.cgi