ISAPI Extension troubleshooting UNDER IIS 6.0
Posted on 2005-05-02
I asked a question in January amd was given the reply that I need to go to my developers. I argued wrongly and after being told why I was wrong I realized that I actually got help (by being told to get those dfevelopers to do something and stop wasting my time). That was question
Now the developers have reqritten the extension. It is much much faster that before for several reasons. 1 they added caching to memory for images. If a client brings up their image the dynamically created thumb will be held in memory for 30 seconds so the enxt request will be instant.
Many of ther previous isues are resolved. One issue I have though is the app occassionally takes forever to load an image and only killing w3wp.exe in Task manager solves that issue.
Reading about app pools and trying to learn something I went in and made these changes
Increase Worker processes to 5 Default 1
Recycle worker processes after 500 requests Default off
Shutdown worker processes after idle for 5 minutes Default 20 (OFF)
Enable pinging 5 seconds (default 60)
Rapid fail protection 3 and 3 default 5 and 5
This is the ONLY app on this server. It dynamically creates a thumbnail from a full size image to the size needed based on the area of the site the user is in at the time of the request. A ColdFusion web site on another server calls the dll with whatever paramaters are required. There is also an editor that allows the users to crop, resize, RED reduction etc etc all using the same dll (ISAPI Extension).
My question is broad, I know, but what did those changes I make do? They helped tremendously. The app does not hang anymore at all. But I have no idea what I did and we have only a test locad on the server right now so I do not know what will happen when I go live.
Can I increase WP's to a much higher number like 50 or is that a waste of time. Are there any other settings I shiould/could make to help optimize performance stability. Unluckily the developer admits to not having the IIS knowledge to make these suggestions. He dos understand the importance of knowing this info but he has basically modified one of his applications for us and has gone way beyond what we paid him to do. So I am at a crossroads now and even though I understand that the developer is the key to knowing what is happening I was hoping that I could get some assistance in understanding how to monitor/troubleshoot IIS 6 so I can give the developer some feedback and he can better understand what is needed to make the application more stable.
The machine is an IBM 360 Quad Xeon capable with 2 XEON MP Processors 1.6Ghz, 2meg L2 cache. It has 4 Gig of Ram. As I mentioned this is a decicated server to only this application. The images reside on two NAS servers on the same local network connected via copper Gigabit links. Currently I see very little performance difference between locally accessed images and network accessed images.
Any details on changing the app pool settings and other configs in IIS 60 appreciated.Running in default IIS 6.0 mode..