I have a website with about 1.5M pages. I am condensing pages that do not have large amounts of content to improve the quality of the site. As a result, I have about 70K pages that I have added a canonical link to, pointing towards the new master page for the content.
Now I want to completely work the existing pages out of the system. I want to 301 redirect the existing pages to the new master pages that the content now resides on. I am running IIS and normally would use RewriteMaps (Apache). I am concerned that adding 70k lines to my web.config, to be parsed for every URL, is going to affect performance.
Any suggestions on a known/tested way to accomplish this?