Question

Playing and trying to see how fast node.js can serve a static file from disk using apache bench

ab -r -n 10000 -c 1000 http://server:8080/loadtestfile.txt

I’ve got ulimit problem on Ubuntu 11.04 x64 VirtualBox VM on OSX Lion

(node) Hit max file limit. Increase "ulimit - n"

I can’t increase the limit anymore.

$ ulimit -n 1000000
$ limit -n 1100000
-su: ulimit: open files: cannot modify limit: Operation not permitted

Is this the right way to force node.js to reload the file from disk to serve each HTTP request? How do I increase the limit beyond 1000000?

Normal curl request works:

curl http://server:8080/loadtestfile.txt

Code

var sys = require('sys'),
http = require('http'),
fs = require('fs'),
index;

http.createServer(function(request, response) {

fs.readFile('./loadtestfile.txt', function (err, data) {

    response.writeHeader(200, {"Content-Type": "text/plain"});
    response.write(data);
    response.end();
 });

}).listen(8080);

Answer 1

Ideally, your application would run within the limits given to it; it should cleanly handle accept(2) returning an error condition with errno(3) set to EMFILE or ENFILE by not trying to accept another connection until an existing connection dies.

However, fixing the application to handle this case gracefully can be difficult; if you just want to raise your limits further to do more testing, there are two possibilities.

• Edit /etc/security/limits.conf to raise the hard limit for your user account for the nofile limit to something much higher and then log in your user account again.

• Do your testing in a root shell; you could either log in as root directly or use sudo -s or su to start the shell, then run the ulimit -n command from there.

The difficulty is because raising limits requires administrative access. (When you’ve got a few hundred users on the system simultaneously, you want to keep them playing nice…)

However, I’m going to guess that your application will also run into the system-wide maximum number of open files limit; that is configured via /proc/sys/fs/file-max. Raise that limit too, if the application complains.