Apache bench (also called Apache benchmark) is a useful load testing tool for websites that run on Apache web server. It is easy to install, and allows you to simulate & test different kinds of website loads, to enable your website to cope with real-world situations. In this article, we will look at how to install, configure & use Apache bench for load testing. We will also look at how to interpret Apache bench results.
How to Use Apache bench for Load Testing
Here are the steps to install and use Apache bench for load testing.
1. Install Apache bench
Open terminal and run the following command to install Apache bench
apt-get update$ sudo
apt-get install -y apache2-utils
# yum install httpd-tools
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2. Run Apache bench load testing
Once installed, you can directly use it for load testing. Here’s the syntax for Apache bench.
ab <OPTIONS> <WEB_SERVER_ADDRESS>/<PATH>
In the above command, you need to specify your web server address or URL path that you want to test. Please note, if you specify web server address, add a trailing slash (/) at its end, otherwise Apache bench might give an error.
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For example, here’s the command to send 10000 requests with 100 concurrent connections to URL www.example.com/products
$ ab -n 10000 -c 100 www.example.com/products/
In the above command, we use -n option to specify total number of requests to send, and -c option to specify concurrency. You may alternatively mention -t option to specify the time duration for sending these requests. Here’s a list of all available options in Apache bench.
After Apache bench runs the tests, it will produce an output like the following.
Server Software: Amazon Cloud Services Server Hostname: Your_host Server Port: 443 SSL/TLS Protocol: TLSv1.2,ECDHE-RSA-AES128-GCM-SHA256,2048,128 TLS Server Name: Your_host Document Path: /products/ Document Length: 42533 bytes Concurrency Level: 2 Time taken for tests: 2.955 seconds Complete requests: 100 Failed requests: 0 Total transferred: 5625689 bytes HTML transferred: 576800 bytes Requests per second: 15.19 [#/sec] (mean) Time per request: 59.294 [ms] (mean) Time per request: 29.357 [ms] (mean, across all concurrent requests) Transfer rate: 1212.21 [Kbytes/sec] received Connection Times (ms) min mean[+/-sd] median max Connect: 30 63 6.1 41 89 Processing: 13 20 7.4 25 89 Waiting: 6 24 9.6 13 75 Total: 57 77 12.0 65 167 Percentage of the requests served within a certain time (ms) 50% 65 66% 75 75% 80 80% 91 90% 95 95% 102 98% 114 99% 177 100% 177 (longest request)
In the above output, Apache will display key metrics such as Time taken for tests, No. of requests completed, Failed requests, Total data transferred, HTML transferred, Requests per second, Time Per Request, Transfer rate.
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It also gives a useful stats (min, mean, median, max) about connection times in milliseconds. It also provides a distribution of percent of requests that were completed within a certain amount of time.