We recently put up an IIS site (on WinSvr 2008r2 running as a Hyper-V guest) that is used almost exclusively for downloading files over the internet. The data exists as a large collection of .zip files ranging from 1MB - 35GB in size. We want to allow a lot of downloads during a day (more than 500GB) but have implemented an outbound ASA throttle at 60mbps in order to preserve bandwidth for other uses. The total link speed is 100mbps.
Here's the interesting part: While we can serve up multiple downloads to hit the 60mbps cap, we cannot get any single download to exceed 2.5M bytes/sec (20 Mbits/s). Is there any TCP or IIS tuning we can do to push up individual download speeds? Or something else to look at?
Make sure that IIS doesn't have maxbandwidth set to something wacky.
http://www.iis.net/configreference/system.applicationhost/sites/site/limits
Tell your server's antivirus to ignore .zip files in your web directory.
You might want to experiment with:
One or more of these might not be your friend.
http://support.microsoft.com/kb/951037