Make sure you know when your Node.js process crashes: output the error to stderr, append it to a file, send it via email, and send it via SMS. Cover all your bases in case of loss of filesystem access or internet connectivity.
Don't just let your server crash on an unhandled error, finish everything you were doing first. Multiple techniques used to ensure your clients don't get socket hang-ups. Cluster support and graceful shutdown on SIGTERM too!