We are considering a SharePoint 2010 configuration where we deploy separate app pools/web applications for each business unit in our company. We would have 10 app pool/web app instances total in that configuration.
Microsoft's current guidance is for 10 app pools max per server, but with the caveat that it is really limited by server memory. Our WFEs current have 8GB RAM each.
How much RAM would be required to host 10 app pools (or more allowing for growth)? Is 8GB enough? Are there any thumbrules for estimating RAM usage per app pool? What other problems would I likely encounter?