ASP.NET Requests Queued and IIS Restarting

[Chris Goodwin]

I have a client that is experiencing a very strange problem on their web
server. Once or twice a day the number of ASP.NET Requests Queued jumps
from 0 to over 4 million in a split second. At this point IIS Terminates,
and the IIS Admin Service and Web Publishing Service Stop and auto-restart
(according to their recovery settings). What's odd about this is that there
are usually only a couple of users in the web application at this time, and
there definitely are not 4 million entries in the web server logs. Has
anyone experienced anything like this? We suspect it could be related to
the SiteMinder ISAPI filter that is installed on the server (which is being
used for SSO).

Thanks,

Chris Goodwin
(e-mail address removed)

 

[Steven Cheng[MSFT]]

Hi Chris,

Thanks for posting here. From your description, you found that once or
twice a day their will ocuur over 4 million queued requests in your asp.net
web application when the actually connected user are much less than the
value which cause the IIS server terminate. Also there is a ISAPI
installed on the server ,yes?

As for this problem, I've some further questions on it:
1. What's the server's os version and are you using IIS5 or IIS6?

2.AS you mentioned the ISAPI, then have you tried stop using this ISAPI to
see whether the problem still remains.

3. Also, you can try creating a new simple web appllication on the
server(with the ISAPI) using to see whether such a simple app still suffer
the issue.

I'm not sure whether you've read the following tech article, may be it'll
be helpful for troubleshooting
#ASP.NET Performance Monitoring, and When to Alert Administrators
http://msdn.microsoft.com/library/en-us/dnaspp/html/monitor_perf.asp?frame=t
rue

In addtion, looking at the nature of this issue, it would require intensive
troubleshooting which would be done quickly and effectively with direct
assistance from a Microsoft Support Professional through Microsoft Product
Support Services. You can contact Microsoft Product Support directly to
discuss additional support options you may have available, by contacting us
at 1-(800)936-5800 or by choosing one of the options listed at
http://support.microsoft.com/default.aspx?scid=sz;en-us;top. If this is not
an urgent issue and your would like us to create an incident for you and
have Microsoft Customer Service Representative contact you directly,
please send email to (remove "online." from this no Spam email address):
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Regards,

Steven Cheng
Microsoft Online Support

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[Chris Goodwin]

Yes, there is an ISAPI filter on the server. The client is using
Netegrity's SiteMinder for SSO / Security provisioning

1. Windows 2000 Server SP4 - IIS5
2. We are in the process of disabling the Netegrity Siteminder ISAPI filter
to test this.
3. The problem with this is that it typically happens once or twice a day,
sometimes as many as 5 or 6 times, sometimes it goes for days without an
issue. We have yet to actually reproduce the problem when someone is
watching the server. Sometimes the last request that is logged is a simple
get for a static image, sometimes it's for an aspx page, and it never seems
to happen at the same time, or on the same page.

The thing I really don't understand is how it is possible to have queued
requests that aren't actually logged in the IIS logs. Is this normal?

We will be working with the client to open a support incident with Microsoft
today.

 

[Steven Cheng[MSFT]]

Hi Chris,

Thanks for your response. This does be a strange thing and I'm not sure the
actual problem occured in it. However, as for the
"how it is possible to have queued requests that aren't actually logged in
the IIS logs."
you mentioned, my understanding is that since the queued requests are the
features of the ASP.NET rather than IIS, as we know, the ASP.NET request
is original pass into IIS and then be routered to the aspnet_isapi.dll and
then processed by the asp.net page handlers. If the problem is in the
ASP.NET, it is likely that the IIS's log can't represent the symptoms of
the problem within the ASP.NET internal. Do you think so? Anyway, hope
you'll soon get the problem resolved. Good Luck!


Regards,

Steven Cheng
Microsoft Online Support

Get Secure! www.microsoft.com/security
(This posting is provided "AS IS", with no warranties, and confers no
rights.)

Get Preview at ASP.NET whidbey
http://msdn.microsoft.com/asp.net/whidbey/default.aspx