Scenario:
Simple file upload application using ColdFusion 8 on IIS 6 and Windows 2003 server. The application allows for large files to be uploaded to the server for backend processing. File sizes range from 10MB - 300 MB.
Problem:
File upload fails for files greater than 30MB.
Analysis:
Several options were investigated including the following:
- Maximum upload file size in ColdFusion (located in the CF administrator)
- IIS time out settings
- IIS minbytespersec settings in the Metabase.xml file
None of these worked. We also spoke with the ISP regarding throttling on the firewall, which was not the issue.
Resolution:
The server was locked down as part of our security policy with UrlScan installed to mask certain server information. One of the settings in options in urlscan.ini is MaxAllowedContentLength which is set to 30MB by defualt. Here is an excerpt from the Technet article:
MaxAllowedContentLength=30000000
The MaxAllowedContentLength enforces a maximum value, in bytes, on the content length. It does not actually prevent the server from reading more data than what this value is set to. For example, if a client makes a chunk transfer encoded POST, this option does not track the size of the entity in the request. The default value is 30000000
Increasing this value to 300MB allowed the uploads to work correctly. The full article can be found at http://technet.microsoft.com/en-us/library/cc751376.aspx
Thanks goes to Rackspace UK technical support, even thought they didn't identify the exact problem, their input helped tremendously in finding a solution. Rackspace UK is the best dedicated hosting solution ever!
Happy Coding!
