Can you prevent IIS7/8 from monitoring UNC paths for web.config changes?

Question

I have a web server which loads imagery from UNC filesystems for each site. These are added as a virtual directory for each site. These filesystems can contain thousands of folders and it appears that IIS is monitoring each folder for changes, which means the server eventually runs out of file handles for the UNC filesystem. I've increased the number, but this only puts off the issue. Is there a way of telling IIS not to monitor for changes on UNC filesystems?

I've looked at EnableChangeNotificationForUNC but there isn't an ASP entry under HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\ on the machine so I assume this is out of date.

Answer 1

For virtual directories there is the allowSubDirConfig property which defaults to true. This controls whether sub directories are checked for web.config files. Set the default to false or set it on a per virtual directory basis. Both are in the ApplicationHost.config file.

<virtualDirectory path="/Pic777" physicalPath="\\Serv4\images\777" allowSubDirConfig="false" />

References:

• AllowSubDirConfig Clarification (blog entry).
• IIS7’s performance slower than IIS6 (blog entry).