IIS: We encounter "Not enough quota is available to proces..

Hi all,

First of all, I am posting this to IIS newsgroup, even though my underlying
problem could be an OS issue.

I have a .Net 2.0 web application using IIS 6.0 on 4CPU Dell Xeon 2GB RAM
machines.

Our application spawns multiple threads to handle ASP.Net incoming requests,
and our application calls a native STA Win32 DLL to talk to the backend
serversystem. We post a message to the Windows message queue using
PostThreadMessage() to talk to the Win32 DLL.

After about 2 hours of the server continuously running, we eventually see
this error in our web log:

System.ComponentModel.Win32Exception: Not enough quota is available to
process this command

We see this error after a call to PostThreadMessage()
Once we see this error message, our server can no longer take any further
incoming requests.

We are wondering what this error means.
We have noticed that the ASP.Net Request Queue seems to grow quite large.
(We have looked up on the web that we can tune the ASP Metabase settings to
tune the Queue size, but we are not sure this is the problem)

We are not sure what resource limit we are encountering.
Is it ASP.Net Request queue or something else.

Also, we have had difficulty reproducing this error in our QA environment.
We have only been able to reproduce it in production or beta enviroments.

- John Sun

I suspect the underlying problem is with your application and not
IIS/OS. A growing ASP.Net queue usually indicates a performance problem
with the ASP.Net application. Basically, either the ASP.Net application
is not finishing requests fast enough, or ASP.Net is starved of worker
threads to hand requests to the ASP.Net application. Either would cause
ASP.Net to queue. Of course, there are other ways to get ASP.Net to
queue improperly under resource-constrained situations on CPU/Memory,
but with STA locking up resources, I doubt it.

I would attach a debugger to the process that returns
"System.ComponentModel.Win32Exception" and see what is going on within
that processbefore/during the issue. Is it memory, threads, handles,
CPU being exhausted. Perfmon and TaskManager can also help capture
information.

In short, you are better off debugging your issue than looking for
someone else with a "similar" problem because we are talking about
arbitrary code execution here.


//David
http://w3-4u.blogspot.com
http://blogs.msdn.com/David.Wang
//



John Sun wrote:
> Hi all,
>
> First of all, I am posting this to IIS newsgroup, even though my underlying
> problem could be an OS issue.
>
> I have a .Net 2.0 web application using IIS 6.0 on 4CPU Dell Xeon 2GB RAM
> machines.
>
> Our application spawns multiple threads to handle ASP.Net incoming requests,
> and our application calls a native STA Win32 DLL to talk to the backend
> serversystem. We post a message to the Windows message queue using
> PostThreadMessage() to talk to the Win32 DLL.
>
> After about 2 hours of the server continuously running, we eventually see
> this error in our web log:
>
> System.ComponentModel.Win32Exception: Not enough quota is available to
> process this command
>
> We see this error after a call to PostThreadMessage()
> Once we see this error message, our server can no longer take any further
> incoming requests.
>
> We are wondering what this error means.
> We have noticed that the ASP.Net Request Queue seems to grow quite large.
> (We have looked up on the web that we can tune the ASP Metabase settings to
> tune the Queue size, but we are not sure this is the problem)
>
> We are not sure what resource limit we are encountering.
> Is it ASP.Net Request queue or something else.
>
> Also, we have had difficulty reproducing this error in our QA environment.
> We have only been able to reproduce it in production or beta enviroments.
>
> - John Sun