thinking about sessions and databases

[eluser]Sean Murphy[/eluser]
Unless you're using a shared disk like NFS across all of your application servers, the more servers you have, the less efficient file caching will become.

Depending on the importance of what you're storing in your sessions, using only memcached may be an option. It would be faster than any combination of DB or file storage, and scales much better. The only thing is if one of your memcached servers goes down you have to be okay with loosing all the session data. A shopping cart would be one case where that wouldn't be acceptable.