Strange IIS Behaviour
Unfortunately the only “supported” web servers offered by our IT department are servers running windows and IIS. As a result I have to deal with unreliable performance and when we do have a problem its basically impossible to debug. When I place a call to engineering about a problem the answer I always get is: “uhhh…ok, well we’ll reboot the server and see if that fixes it.” Brilliant solution.
Well, anyway the other day I noticed a strange problem. I wrote a script to email me any web site errors that occur. Previously the errors would only be submitted if the person who received the error clicked “submit error report.” I was curious to see how many people don’t bother so I decided to submit the reports automatically. The result, I think people clicked “submit” roughly 10 or 20% of the time.
Anyway, I was looking through the errors and I noticed quite a few created by search engines scanning the site (broken link errors and such). However, I noticed a few errors on an area of the site that supposedly no longer existed. I checked the server and sure enough, the files that were causing the errors no longer existed. Just out of curiosity I pointed a browser at the page and was confused when content was returned. Most of the graphics weren’t visible, since they’d been deleted, but all the text was there. I couldn’t figure out why a file I had deleted months ago was still being served so I checked the directory once again to verify that yes the file was deleted. It was; no where to be found. I checked some of the other files I’d deleted in that folder and they were also still being served up. I figured it was a caching problem but after clearing the IIS cache, clicking “expire content immediately”, neither of which worked I was stumped. So, I decided to create a file with the same name that would redirect to the home page. I refreshed my browser and sure enough it worked. Then I deleted the file just to see if it would still be served up. Strangely enough this time it actually deleted the file and I got a “file not found” error. Strange strange strange.