Improving Scalability by Optimizing IIS 6.0 Queues

  • Article

Applies To: Windows Server 2003, Windows Server 2003 with SP1

A request queue holds a collection of one or more requests waiting to be executed. Request queues can develop when your site experiences high traffic volumes, or if your site blocks to wait for database processing. Large queues, or queues that are not cleared quickly, impact scalability by limiting the number of requests the server can process and by reducing throughput. More importantly, if users are forced to wait for a response from your server, they might perceive that the site is not available and click the Stop button on their Web browser. In this situation, the queuing problem grows because clicking the Stop button can fill a queue with requests that are no longer connected to a client's browser. If your site routinely develops queues, you might dramatically improve scalability and availability by adjusting the number of requests that can wait in a queue. You can set limits for the following request queues:

  • TCP/IP queue

  • Kernel request queue

  • ASP request queue

  • ASP.NET request queues