Hi,

We are migrating an application from IIS6 X86 to IIS7 X64 and are noticing a huge increase in the memory usage of the worker process.

On the IIS6 box, the mem usage sits between 200MB and 300MB even when we run our load tester against the site. We can see the usage increase but it is very quickly reclaimed again so that it stays within that range.

The same load test run against the IIS7 box sees memory usage spiral very quickly up to over 2GB and it doesn't seem to get reclaimed.

It seems that there is a problem with the garbage collection but I don't know why the same application is operating differently between IIS6 X86 and IIS7 X64.

Anybody experience this same problem or able to shed some light on this?

Thanks,

Jason

PS. I have an HTTP handler that closes and disposes the session at the end of every request. Is it correct to dispose the session here? Do I need to close the session factory or do other tasks to correctly free all resources?

I set the enable32BitAppOn64 flag to True on the application pool and now the memory usage is exactly the same as I am seeing on the x86 IIS6 box so the problem definitely seems to be related to x64.

Our app never really goes above 400MB usage so this shouldn't cause any problems for us. Still working with someone at MS to figure out why the x64 mem usage is so much higher though.

Jason