centos or tomcat restarting – how to monitor?-Collection of common programming errors

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)

  1. To start with, I would use uptime to definitively determine if the host is being rebooted or not. Your range of potential problems will be a fraction once you find this out.