Upgrade failed - what needs to be restored? Unfortunately I tried to (auto)upgrade to v2.5.latest on a live site (after testing on another development (but different site)) and it failed resulting in the site being down. What is the best way to restore the site to pre-upgrade and working state? I plan to


Remove the existing database and replace with the one created by the
backup process - that part seemed to go OK. 
Replace the /craft/app directory from the version that matches the database backup.


Are there other files/things I need to do to recover the situation?
That should do it!

Auto-updating to 2.5 is causing a few people headaches, mainly because people are bumping up against their php.ini setting limitations. It's a pretty significant update, requiring pretty significant server resources to handle the transition.

Once you've successfully rolled back, I'd recommend performing a manual update. This takes a lot of pressure off of your server, and only leans on your server resources to run the database migrations (which definitely shouldn't cause any overloads).