The qos-handler AuthTrans directive must be the first AuthTrans configured in the default object in order to work properly. The role of the quality of service handler is to examine the current statistics for the virtual server, virtual server class, and global server, and enforce the limits by returning an error.
Sun Java System Web Server includes a built-in sample quality of service handler SAF, called qos-handler. This SAF logs when limits are reached, and returns 503 "Server busy" to the server so that it can be processed by NSAPI.
Sun Java System Web Server also includes a built-in sample error SAF called qos-error which returns an error page stating which limits caused the 503 error and the value of the statistic that triggered the limit. You may want to alter the sample code to provide different error information.
For more information on these SAFs and how to use them, see the Sun Java System Web Server 6.1 SP12 NSAPI Programmer’s Guide.