IIS restrictions?

Question

IIS

IIS is raised on the local server, there are several sites on it. When about 140-160 users connect on one of the sites, connecting a new one becomes impossible. those. an http request is sent, but the response does not reach, such as the page is loading ... At the same time, the load on the processor is not more than 15% and free memory is more than 50%. And the rest of the sites on the server are loaded without problems. It seems that in the pool settings there is a limit on the number of sessions ...
Pool

settings Site settings

Tell me what could be the problem ...

Answer 1

Look also at disk queues - bottlenecks are not limited to memory and processor.
There may also be locks at the database level, etc.

Answer 2

If it doesn't help, see here: How to increase thread-pool threads on IIS 7.0

Answer 3

I would also look at how the application is written and fasten elmah code.google.com/p/elmah/ to it and see if requests reach the server

Answer 4

If it's about hanging requests, then you need to look at the request queue in the process pool.
If there are a large number of rows, it may indicate a problem in processing the request.
It is also worth considering the option when each request creates its own thread or timer or leaves an open connection to the database or file.