We currently have a windows server 2003 dedicated server running a fairly large classic ASP website on IIS 6. This server has 2GB of RAM and a single core AMD Athlon 3500+ processor.
We are moving over to another dedicated server with Windows Server 2008 R2, IIS 7.5, a dual-core processor AMD Opteron 2.1 GHz and 48GB RAM.
There is a noticeable drop in performance on the website and I was wondering if anyone could offer some advice in how to correct this. The problem seems to arise when Session variables are used.
The obvious difference is the clock speed of the processors, but having carried out various timing tests on both servers they perform about the same. For instance, the following code runs in pretty much the same time on both servers:
Dim endTime
Dim startTime: startTime = timer
Dim n
For n = 0 to 10000000
next
endTime = timer
response.write "Time taken: " & (endTime-startTime)*1000 & "ms"
If however I test the following code and include a Session variable...
Session("Test") = 5
Dim endTime
Dim startTime: startTime = timer
Dim test
Dim n
For n = 0 to 10000000
test = Session("Test")
next
endTime = timer
response.write "Time taken: " & (endTime-startTime)*1000 & "ms"
The new server takes between 3-4 times times longer to execute the code than the old server. This is repeatable.
The website uses a lot of Session variables, otherwise I'd look at perhaps an alternative way of maintaining state for a user, but I'd much rather cure the problem at source.
To me, it feels like a configuration issue on the new server, or IIS, or both, but I just can't pinpoint it.
Any help would be appreciated.