eZ Publish Performance Optimization Part 1 of 3: Introduction and Benchmarking

ApacheBench, or "ab", is a small tool bundled with the Apache webserver that is used to check the maximum performance of your webserver or web application. It can only benchmark one URL at a time and does not include images, CSS files or other items included on a webpage. It basically hammers the URL and records how much time the webserver spends on serving the pages.

Concurrency is specified by the parameter -c and number of requests is specified with -n.

Examples

Here is an ab example with eZ Publish running on one server. We fetch 20 requests with concurrency ranging from 1-4. As you will see from the table below, the server scales well with 4 concurrent requests. This is also the maximum performance delivered from this server.

The commands used are as follows:

ab -c 1 -n 20  http://olympia.ezcluster.ez.no/base/
ab -c 2 -n 20 http://olympia.ezcluster.ez.no/base/
ab -c 3 -n 20 http://olympia.ezcluster.ez.no/base/
ab -c 4 -n 20 http://olympia.ezcluster.ez.no/base/

Below is a very simple table that you could create from ab output in order to demonstrate the server's ability to deal with an increasing number of concurrent requests

In this case, the theoretical maximum number of pageviews for this server is about 3 million (35.5*60*60*24) per day.

Here is another sample command and ab's resulting output:

$ ab -c 5 -n 100 http://mycachedsite.example.com/

This is ApacheBench, Version 1.3d <$Revision: 1.73 $> apache-1.3
Copyright (c) 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Copyright (c) 1998-2002 The Apache Software Foundation, http://www.apache.org/

Benchmarking db.no (be patient).....done
Server Software:       Apache/1.3.33
Server Hostname:       db.no
Server Port:           80

Document Path:         /
Document Length:       228 bytes

Concurrency Level:     5
Time taken for tests:  1.424 seconds
Complete requests:     100
Failed requests:       0
Broken pipe errors:    0
Non-2xx responses:     100
Total transferred:     42200 bytes
HTML transferred:      22800 bytes
Requests per second:   70.22 [#/sec] (mean)
Time per request:      71.20 [ms] (mean)
Time per request:      14.24 [ms] (mean, across all concurrent requests)
Transfer rate:         29.63 [Kbytes/sec] received

Connnection Times (ms)

             min mean[+/-sd] median  max

Connect:      13   31   5.5    31   44
Processing:   32   39  26.6    36  294
Waiting:      19   39  26.6    36  294
Total:        32   70  27.6    70  327

 
Percentage of the requests served within a certain time (ms)
 50%    70
 66%    71
 75%    71
 80%    72
 90%    75
 95%    83
 98%   109
 99%   327
100%   327 (last request)

What it is not

Ab is not a tool you can use to generate a natural load on the server. In such a case, you should use a tool like siege (described later in this article).

Further help

You can also use ab -help to see a list of all parameters ab can take. You can for example have ab log into a website with htauthentication.