You may also want to consider using the upstart utility. It will allow you to start, stop and restart you node application like a service. Upstart can configured to automatically restart your application if it crashes.
Install upstart:
sudo apt-get install upstart
Create a simple script for your application that will look something like:
#!upstart
description "my app"
start on started mountall
stop on shutdown
# Automatically Respawn:
respawn
respawn limit 99 5
env NODE_ENV=production
exec node /somepath/myapp/app.js >> /var/log/myapp.log 2>&1
Then copy the script file (myapp.conf) to /etc/init and make sure its marked as executable. Your application can then be managed using the following commands:
sudo start myapp
sudo stop myapp
sudo restart myapp