IIS 7 and Above
IIS does not assign requests correctly to worker processes
Last post Feb 27, 2020 05:37 AM by Yuk Ding
Feb 26, 2020 08:56 AM|motobit|LINK
2 sockets, 12 core, Win 2012 R2, IIS/7.5, ASP, Helicon URL rewrite
App pool with 10 worker processes
IIS works normaly and assigns requests equally to worker processes for some time - minutes, hours. But after this, IIS use only one process, the process is overloaded (100th of requests in queue, most of them active), other worker processes in the
app pool are almost idle.
IIS response time is in 10th of seconds.
Recycle of the pool solves the situation, but only for some minutes, hours. And then again.
Feb 26, 2020 04:49 PM|carehart|LINK
That would be odd, at least with default settings. But you could have configured something that could be influencing it, or you may have some unusual problem.
Let's start with some clarifications:
Feb 26, 2020 05:00 PM|lextm|LINK
The actual load distribution is controlled deep down inside IIS, so your only hope is to go through Microsoft support by opening a support case via
However, you should seriously consider a multi server setup load balancing cluster. The web garden approach (multi process application pool) is not widely used.
Feb 27, 2020 05:37 AM|Yuk Ding|LINK
This issue could be complicated. You may need to capture dump file and etl log. So we can check what happened there. It is also important to capture the last request before other worker process down.
As lex said, if this is making business impact, please open a support ticket and involve professional engineer for help.