Problems with stale sessions and cached pages

I'm using Apache+Mongrel with Ruby 1.86 and Rails 1.2.3. I'm using auth_generator for user sessions, MySQL-based application sessions and comatose for my content mgmt system. Every now and again, auth_generator gets confused with who's logged in and once in a whilst, when someone updates an article using comatose, the page cache isn't being flushed, even after forcing a page cache flush with the provided comatose link to do just that.

Both of these problems are corrected by restarting the mongrel cluster ... but I'm concerned that if/when the site starts to get busy then I won't be able to keep restarting the mongrels without effecting users activities.

Anyone experienced the same ? ... and what does one do about it ?.

Thanks in Advance, Attila