The mod_status module allows a server administrator to find out how well the server is performing. An HTML page is presented that gives the current server statistics in an easily readable form. If required, given a compatible browser, this page can be automatically refreshed. Another page gives a simple machine-readable list of the current server state.

This Apache module is written in C. It is compiled by default, so all you have to do to use it is enable it in your configuration file:

<Location /status>
    SetHandler server-status

For security reasons you will probably want to limit access to it. If you have installed Apache according to the instructions given in this book, you will find a prepared configuration section in httpd.conf. To enable use of the mod_status module, just uncomment it:

ExtendedStatus On
<Location /status>
    SetHandler server-status
    Order deny,allow
    Deny from all
    Allow from localhost

You can now access server statistics by using a web browser to access the page http://localhost/status (as long as your server recognizes localhost).

The details given by mod_status are:

  • The number of children serving requests

  • The number of idle children

  • The status of each child, the number of requests that child has performed and the total number of bytes served by the child

  • The total number of accesses and the total bytes served

  • The time the server was last started/restarted and for how long it has been running

  • Averages giving the number of requests per second, the number of bytes served per second, and the number of bytes per request

  • The current percentage of the CPU being used by each child and in total by Apache

  • The current hosts and requests being processed

In Chapter 5 you can read about Apache::VMonitor, which is a more advanced sibling of mod_status.

Turning the ExtendedStatus mode on is not recommended for high-performance production sites, as it adds overhead to the request response times.