I have the following web server setup:

  • Windows 2k8 x64 (pretty beefy, 32 GB of memory, recent processor)
  • IIS7.5
  • 1 Windows 7 32-bit Test client

On occasion ( < once per month) Our application downloads large MSI installer files via an HTTP URL from the server Files are around 150 MB). Recently we have migrated our server platform to Windows Server 2008. We have had a few cases where the HTTP downloads are VERY slow.

I check the IIS logs on the server, and the files seem to be downloaded in increments of 0 - 2048 bytes. All lines in the W3SVC logs end like this:

... /ABC.msi ... 206 0 1768

I am assuming 1768 is the chunk of data in bytes that was downloaded for that pass.

Whereas before it was taking our 150 MB files 15-20 minutes to download (from a client like IE's file download functionality, or event BITS), it is now taking hours.

Is there something in IIS 7 throttling bandwidth on these files? There would rarely be more than 1 or 2 of the transfers occurring simultaneously, and our tests are only from 1 client.

I've searched all over the place, and the "Application Request Routing" seems like a place to look, but I can't see this feature icon in the IIS management tool. Has anyone else seen similar behavior?

  • Similar problem here. Do you managed to solve the problem? – Eduardo Molteni Sep 23 '11 at 22:05

It turns out it was the actual speed of the network that was slow, not IIS or the app. That was the first question I asked and I was assured that the network was fine, but turns out it was not.

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