cripox's questions

I want to make a server for my static content.
I need to serve some 3-10 mb files - a lot. (I will also put on this server some .js and .css and images from my websites).
I thought of nginx and G-WAN ( http://trustleap.com/ ).
What I don't know is what resources are needed for serving static content? How much RAM is used for each file transfer?
If I will go with a 256 mb (or 512 mb) VPS with good port and huge bandwhich how many hits /seconds will I be able to serve (3-10 mb files)? (I know "it depends" - but please give me a rough estimation based on experience or theory).
There are not a lot of files, just often downloaded - should I consider caching, or this will only use my memory needed for serving hits?

I'm a almost totally beginner to server administration.

I recently got a VPS box on nixcom.ca to learn the stuff, installed nginx and tomcat. The issue is that almost after every one or two days of working, when I go to see my test websites, the tomcat server is down. The nginx site at :80 is ok, but the one at :8080 is down. I want to mention that the tomcat is not configured to start automatically after os start.

There were some issues in the past with the Nix node my VPS is on, but I think they fixed that.

So, my problem is that I don't know if the whole box is being restarting (and ngix is just started up at boot, but not tomcat) or that tomcat is crashing. I looked in the logs from tomcat and I can see nothing about any errors/crashes (there is virtually no trafic on that websites).

If I go to the VPS Control Center on Nix -> logs, I can see only reboots and reinstalls that I did, not any crash.

How can I monitor / see in the logs what happened?

My setup:
Debian 5 XEN 32Bit
512mb RAM
Nginx
Tomcat 6 installed manually
jre1.6.0_21 - installed manually
JAVA_OPTS="-Xms400m -Xmx400m -XX:PermSize=128m -XX:MaxPermSize=256m"
CATALINA_OPTS=-Xms400m -Xmx400m -XXPermSize=128m -XX:MaxPermSize=256m"
I have a small Grails application hosted.
There is no mail or database software installed. (Using Grails with the in memory hsqldb db)