I\'m using Node\'s Express w/ Connect middleware. Connect\'s memory session store isn\'t fit for production:
Warning: connection.session() Memo
Another good option is memcached. The session states are lost if memcached is restarted, but there is virtually never any reason to do that. You can leave the cache running all the time even when you restart your app server. Access to the session data is virtually instantaneous and memcached will run happily with whatever (appropriate) amount of memory you give it. And I've never seen memcached crash (on Linux).
https://github.com/elbart/node-memcache
Things to keep in mind about memcached generally:
Neither of these should be an issue with session storage; just with generalized caching.