Recently we moved our server from testing to production.
We had an issue with caching some referenced scripts so we needed to edit site.master and put some artificial query parameters on our referenced scripts.
From what I thought you wouldn't need to restart IIS simply modifying a .master page, but the other day I tried uploading a handful .master pages because we eliminated some code on them, and the site went down until we restarted IIS.
Any insight to the way IIS and MASTER pages work would be stellar.
Thank You for your help.
Generally speaking you wouldn't necessarily need to restart your website for a change in your master page. However, if you modify the code-behind you need to compile the site, because Sitefinity is a Web Application Project, not a Web Site Project. This means the full site is compiled to a DLL, so any changes in the code require a new compile to be run and pushed to your site.
In addition, Sitefinity makes use of caching to improve performance, so you might need to restart the site to clear the cache for any changes to things like master pages or user control (ascx) files as well.
I hope this is helpful!