Foglight Evolve 9.2 - Performance Tuning Field Guide

JDK with IPv6 on Linux

Foglight® Management Servers running on a VMware® Linux® x86_64 image fail to start up and a "java.net.BindException: Cannot assign requested address exception" is raised.

This is a JDK issue with IPv6 on Linux, not a true High Availability issue. It also impacts standalone servers. However, the issue is documented here because it occurs when the JBoss® cluster service is starting up.

Workaround: Start the Management Server with the following command:

-Djava.net.preferIPv4Stack=true

For more information, see: the JGroups FAQ (http://community.jboss.org/wiki/JGroupsFAQ) and Oracle® Bugs for it (http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6521974).

Management Server Automatically Restarted

Sometimes, after what appears to be a normal and successful startup, an HA server would be automatically shut down and restarted. The most likely reason for this is a misconfiguration of health check URL in the restart_monitor.config file.

For example, you may have reconfigured the HTTP port of the Foglight® Management Server or reconfigured the IP address that the server is bound to, but forgotten to reconfigure the health check URL of the restarter. If the restarter cannot contact the Management Server for health check, it considers the Management Server not responsive and restarts it.

You can check the server_restarter_xxxx-xx-xx_xxxxx_xxx.log file to determine if this scenario is what caused the restart. If so, edit the restart_monitor.config file by locating the line beginning with health.check.url and configuring the URL properly.

Other JGroup Related Issues and Information

ERROR org.jgroups.protocols.UDP max_bundle_size (64000_ is greater than the largest TP fragmentation size (8000):

https://jira.jboss.org/browse/JGRP-798

“Cross-talk” can occur between servers on different clusters:

https://jira.jboss.org/browse/JGRP-614

Agent Tuning

This chapter provides information about the agent-related options that can have an effect on performance and describes the applicable performance-related options.