Migrate RRD Files between Architectures

If you migrate an RRD-based tool like SmokePing, Cacti or ZeroD you may run into the problem, that the target system can no longer use the historic data, if the default number representation changes (big/little endian, 3264 Bit, …).

In all these cases the following procedure should work. It’s important you dump on the original architecture and restore on the target system.

Java VisualVM

For quick analysis of the options and health of a Java VM I used the jconsole tool (part of JDK) in the past. But that changed.

SNMP Monitoring in Java VM

SNMP is not really simple, but quite useful, if you want to run standard monitoring tools like Nagios, Zero RRD or Cacti.

Even though Java offers JMX over RMI for runtime information like thread and memory consumption, you can also activate SNMP to read at least a subset.

Reduce Kernel Messages in rsyslogd

In the standard rsyslog setup of Ubuntu a kernel message goes to 3 log files (syslog, messages and kern.log), i.e. running LOG targets in your firewall setup can really hog your /var/log volume.

I decided to simply discard the kernel messages after logging them to kern.log.

Monitoring RAID in Nagios

Using RAID to improve availability is fine, but don’t forget to monitor it properly. Otherwise you will never know, that half of your mirror has already gone out of service for months.

Nagios Check for Critical Updates

If you are tired of scanning all kind of CERT advisories in your mailbox and you are running a nice Debian-based landscape using mostly package-based software, you should consider using check_apt from the Nagios plugins.

Zero Frontend Upgrade

The Zero Frontend is currently facing a major upgrade or tuning, introducing views to aggregate components from different hosts.

Popups for the graphs are now integrated into the same window, there is an automatic refresh.