Published on: January 4, 2011 by Subin M.
Scenario:
I will introduce two benchmarking tools which are helpful in Apache performance monitoring : ab & httperf with some other utilities.
1. ab is shipped with most linux distributions. It is used in apache performance monitoring to simulate load test on to your webserver and check how it behaves during such situations. It is run from the command line and the command is ab followed by the required options and the name of a website served by the server that you need to test. There are two ways to which you can run the test. One is to run the ab tool in the same machine where Apache is installed. The sencond is the practical way which is to run the tool to a remote webserver which helps in taking into account the network related accessibility issues. Lets see how to use it.
The most common options of ab are -n and -c. A test to www.google.com would be as below:
root@sage3-desktop:~# ab -n 100 -c 10 http://www.google.com/
This is ApacheBench, Version 2.3 <$Revision: 655654 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/
Benchmarking www.google.com (be patient)…..done
Server Software: gws
Server Hostname: www.google.com
Server Port: 80
Document Path: /
Document Length: 221 bytes
Concurrency Level: 10
Time taken for tests: 1.455 seconds
Complete requests: 100
Failed requests: 0
Write errors: 0
Non-2xx responses: 100
Total transferred: 83000 bytes
HTML transferred: 22100 bytes
Requests per second: 68.72 [#/sec] (mean)
Time per request: 145.509 [ms] (mean)
Time per request: 14.551 [ms] (mean, across all concurrent requests)
Transfer rate: 55.70 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 45 49 3.2 48 62
Processing: 89 94 3.3 94 108
Waiting: 89 94 3.3 93 107
Total: 136 143 5.5 142 170
Percentage of the requests served within a certain time (ms)
50% 142
66% 144
75% 144
80% 145
90% 148
95% 155
98% 166
99% 170
100% 170 (longest request)
-n : 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.
-c : Number of multiple requests to perform at a time. Default is one request at a time.
Let me explain the options. -n denotes the total number of requests to send to the webserver in the ab session. By specifying -c 10 we ensure that at any instant of the ab session we keep the webserver busy with 10 requests until the total limit of 100 requests is reached. The requests may be sent through a single connection if the server permits KeepAlive and browser supports persistent connections. The main points in performace to note for are: Failed requests, Connection Times & Transfer rate.
2. httperf Usage :
httperf –hog –server www.google.com –num-conn 50 –rate 10 –timeout 5
-hog : Use as many TCP ports as necessary to generate stats
–server: the host. IP or hostname can be specified
–num-conn : number of connections to create for the session
–rate : create connections at the rate of 10 per second
More simple and direct usage examples can be found at the man page for httperf.
3. Apart from command line tools, there are online websites for available for apache performance monitoring:
http://linuxbox.co.uk/website_performance_test.php
4. Page Speed by Google is an open-source project started at Google to help developers optimize their web pages by applying web performance best practices. Page Speed started as an open-source Firefox/Firebug add-on and is now deployed in third-party products such as Webpagetest.org, Show Slow and Google Webmaster Tools. Please see:
http://code.google.com/speed/page-speed/
Category : Linux
Subin loves to dive deep into the engineering aspects of technology and internet in particular. He has indepth knowledge in various webservers and DNS.
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