Ideas on Troubleshooting IIS 6 on Windows 2003

Question

I wrote a .NET 4.0 web service that sends back data from an applications data storage. Basically, it is accessing remote, structured text files. The request for data would take between 10-14 seconds on average. Within the last 3-4 weeks, the server is now taking about 4 minutes to access that same data. In an attempt to remove the network as an issue, I moved the files I was accessing to the IIS 6.0 server on Windows 2003 and it is still taking about 4 minutes to return data.

I have a .NET 4.0 web service making calls to COBOL access code that accesses the data files. None of the access code nor the files have been changed.

The problem appears to be the IIS server. I can run this web service from my developer work station to access the files at the remote application server, it runs within the 10-14.

Performance: The web service isn't going beyond 50% utilization processor-wise. I haven't looked that closely at the disks, but the server sits idle most of the time.

I'm looking for suggestions on figuring out where to start troubleshooting from.

Thanks, Martin

Answer 1

I'm not a COBOL expert, just posting what I found with one of my COBOL developers in-house.

I ran profiling against the web site, which I wasn't familiar with, and found that it was moving around a lot of data. The COBOL developer in an effort to get the code working as a prototype had the "linkage" moving around large chunks of data. At the start there were 13+ of these large chunks of data moving around in memory. I can't remember the exact error message, but the Profiler mentioned either heavy use in the Virtual Memory or that the application was using heavy paging.

We reworked the application and it uses significantly less memory and appears to be sending data back in less than 2-3 seconds now.

Martin