I'm really not sure where this question would be best asked, so I'm posting this here in an IIS-specific forum, and also over in SQL Server Central for an SSRS-specific audience.
The problem that I'm having is pretty simple to explain, but I have no idea how to diagnose.
We have a Windows Server 2003 R2 machine - pretty powerful machine, Intel Xeon X5670 CPU, 2.93 GHz, 23.9 GB of RAM. The machine is not being taxed whatsoever - the vast majority of the time, the CPU usage is less than 1%, and the memory usage is even lower. The network card is also far from taxed - there is a 1GBPS network card on the machine.
The machine has IIS 6.0 installed, and is running SQL Server Reporting Services 2005. There is a single application pool devoted to the ReportServer, within which is contained the interface for the Reports and for the ReportsServer (/reports and /reportserver).
The issue is the following:
During regular usage of reporting services, what will occasionally happen is that the reports will simply stop being accessible. When attempting to access reporting services through either the /reports or /reportserver pages, it simply sits at the connecting status.
If I look in the IIS logs, I see that there was an attempt to connect, something similar to below:
2012-12-05 16:57:16 W3SVC1 [IP HIDDEN] GET /ReportServer/Pages/ReportViewer.aspx %2fReports%2fChangement+d%27Adresse&rs:Command=Render&rc:Parameters=false&COA_ID=173 80 - 10.156.76.48 Mozilla/5.0+(Windows+NT+5.1;+rv:16.0)+Gecko/20100101+Firefox/16.0 401 2 2148074254 2012-12-05 16:57:16 W3SVC1 [IP HIDDEN] GET /ReportServer/Pages/ReportViewer.aspx %2fReports%2fChangement+d%27Adresse&rs:Command=Render&rc:Parameters=false&COA_ID=173 80 - 10.156.76.48 Mozilla/5.0+(Windows+NT+5.1;+rv:16.0)+Gecko/20100101+Firefox/16.0 401 1 0
But that's where it ends.
The only way to resolve this problem that I've found, has been to stop the application pool associated to reporting services, wait for a bit, then restart the application pool. After this, the site becomes responsive again, and works fine for some time, but then eventually ends up back at the original problem.
If anyone can help me diagnose and fix this problem I'd be most appreciative!