IIS stuck during upload

[danielden]

We're company developing Web product using the following technologies \ environments: IIS 6, Web2003 (SP1), ASP, ASP.Net 1.1-2.0. The product installed on our Farm (3 Web servers), our dev. env. - 5 installations, and in our customer's farms - 10 installations.
We have a very strange problem in one of our customers: when process of file uploading begins - that is performed by ASP engine on server side, all other new request to ASP engines are waiting in queue until the uploading is finished. This can be seen by ASP engine counters such as:
Requests Wait time
Requests Queued
While uploads finishing, the requests queue is immediately empted and all waiting requests are answered. The same time we have no problems with requests to ASP.NET engine - they are working as required with no delays and waiting in request queues.
The uploading working flow is as following:
- Single file: uploaded by default Microsoft ActiveX component on client side. Server side using third party component Persits.Upload.
- Multiple files. Uploaded by Java third party component, Server side - using of ActiveFile.Post.
Because the data uploading is the main feature of our application, the problem stuck most of our user and preventing from them to work.
The such problem does not exists in any other installations. The only difference between them that in problematic environment we have Win2003 SP2, while other products are running in SP1.

[spinal007]

May well be some sort of security upgrade on SP2, I recommend you start digging through MS KB articles and you might find some info...