In what cases should one prefer to use Node.js only as a server in real deployment?
When one does not want to use Node.js only, what plays better with Node.js? Apache or Nginx?
There are several good reasons to stick another webserver in front of Node.js:
I'll caveat the second bullet point by saying you should probably be serving your static files via a CDN, or from behind a caching server like Varnish. If you're doing this it doesn't really matter if the origin is Node or Nginx or Apache.
Caveat with nginx specifically: if you're using websockets, make sure to use a recent version of nginx (>= 1.3.13), since it only just added support for upgrading a connection to use websockets.
Just to add one more reason to pauljz's answer, I use a front end server so that it can serve up 502 error pages when I'm restarting the backend server or it crashes for some reason. This allows your users to never get an error about unable to establish a connection.
It is my belief that using Node to serve static files is fine in all circumstances as long as you know what you're doing. It is certainly a new paradigm to use the application server to serve static files as so many (every?) competing technologies (PHP, Ruby, Python, etc) require a web server like HTTPD or Nginx in front of the application server(s).
Every objective reason I have ever read against serving static files with Node revolves around the idea of using what you know best or using what is perceived as better-tested / more stable. These are very valid reasons practically speaking, but have little purely technical relevance.
Unless you find a feature that is possible with a classic web server that is not possible with Node (and I doubt you will), choose what you know best or what you'd prefer to work with as either approach is fine.
As for Nginx vs Apache -- they will "play" with Node the same. You should compare them without regard to Node.
I believe in facts and benchmarks According to pauljz nginx is better on serving static files,I fear its certainly not true infact its completly opposite to what did he said please check out the link of bechmarks .How node js scaled 2x times better than nginx (4,250 trans/s vs 2,118 trans/s) - especially at the higher concurrency levels. Also check out average response times (0.14s vs 0.23s), longest transaction time (1.10s vs 13.95s) and transaction availability numbers all in node.js's favour. For more please follow the linkhttp://centminmod.com/siegebenchmarks/2013/020313/