For quick analysis of the options and health of a Java VM I used the jconsole tool, that is part of the Java SDK. Now there is also VisualVM, that not only provides information about the options and health (CPU, … Continue reading
I recently tried to optimize an Alfresco 4 installation in a 1GB Ubuntu VM and reduction of the default 512m for MaxPermSize was too much, the Tomcat instance goes down after startup and first call to /alfresco. Considering the remaining … Continue reading
Ubuntu announced to discontinue packaging of Sun/Oracle’s Java for Ubuntu, because Oracle changed the licensing. Please be careful with upgrades on these packages, since it may drop your Java installation on the system, not only the browser plug-in. So I … Continue reading
SNMP is not really simple, but quite a useful protocol, if you want to run standard monitoring tools like Nagios, Zero RRD or Cacti.
Even though Java offers JMX for runtime information like thread and memory consumption, you can also use SNMP to read at least a subset.
In my opinion usage of a standard monitoring tool has several advantages over JMX-based visualization in jconsole or Lambda Probe:
- Statistics fit into centralized reporting, e.g. for SLAs.
- The tools are independent of the Java VM. If the VM freezes, the history is still available