I have about 20 IIS web sites on one Windows 2003 server. One of the websites is for downloading product updates.
What methods/tools are available to me to ensure that the one does not kill the responsiveness of the others?
The first answer is to ensure that this website runs in its own Application pool. This will ensure this site runs in its own worker process, so any errors will not affect the other sites. It also means you can specify different settings for things like Identity, Performance and Pool Health management.
That said, doing this it not going to stop this site using up all the bandwidth available and preventing the other sites working. The easiest answer to this problem is to have this site listen on a IP that is on a separate NIC and network connection, to the other sites. But obviously this involves having 2 upstream connections to your server. If this is not possible then your are going to need to look at some way to balance the traffic, this is something you may want to do do at your router or switch.
You can (and should) set limits on bandwidth for any IIS server that has the potential for inhaling all the bandwidth of a server. In addition you should also (as previously mentioned) have the sites in their own app pool
To throttle the bandwidth used by an individual Web site