Monitoring my production application

Hi everybody,
I'm running different rails applications in a production environment
and I saw that the memory used by mongrels is increasing every day.
What can I do to monitor this memory increasing? (the applications
seems also to be very slow).

Since I've been started my busiest application, each mongrel (4) has
increased by 70-80 Megs and they keep increasing.

Could the problem be a series of mysql connection not closed properly?
if yes, is there a way to monitor this kind of connection?

Thanks for your help!

The company which is hosting one of our sites has installed a system
called Munin, which monitors a lot of information like memory usage,
registrations, number of up/downloads and so on. It's great.

Sorry, that I can't give you much information about it, since, as
it wasn't installed by us, but here is the link to their site:

We had some memory leak (by ImageMagick, when it crashed) and could
easy enough find the source just by comparing times of error logs with
the memory usage profile.

Another useful tool is Exception Notifier Plugin for Rails

That's a good tool, I'll try it.

Thanks Thorsten!

Check out the Scout plugin for monitoring memory usage:

We use this to monitor memory usage, and along with other Scout plugins, try and fix problems like this.

Generally, if you have a leaky app, it could be that you’re opening a file (a log or any other type of file) and not closing it when done.

Disclaimer: I work for the company that built Scout (Highgroove Studios).