When setting up our early SharePoint environments we often had issues with some of the web application pools, at times we ended up changing the defaults for the loadUserProfile and rapidFailProtection settings. We've run SharePoint 2010 Enterprise on Windows 2008 machines under IIS 7.5 but from my understanding the loadUserProfile default setting places it into an IIS 6 behavior, which does not load the User Profile. I'm trying to understand what User Profile is being avoided, and why this is more secure, I have not spent a lot of time with IIS security configurations and have wondered why IIS is better behavior.
The rapidFailProtection I think I understand as its default setting will shut down Web App Pools when applications within it crash, according to its settings, to keep the App Pool from being corrupted. If I am correct.
For some reason our Admin has linked these settings together, or just always refers to them as dependent somehow. I've tried to find a link between them and understand their settings more but haven't really found anything that clearly explains them. I've checked Joel's blog but he refers more to SP 2007 not 2010. Does anyone know what might be linked here, or have a good explanation, or resource, as to why these settings matter?