Tunables are configuration settings that affect the inner workings of the Load Balancer. Most of the per-port configuration is controlled via the web-based administration, and so you may never need to adjust the Load Balancer tunables (the defaults are all sensible). However, for performance tuning, or to adjust the balancer to specific conditions, you may need to add tunables.

How do I add a tunable to the balancer?

Tunables are stored in the configuration file located at balancer/etc/global.cfg, which is found inside the directory where the balancer was installed (typically /usr/local/zeus). To add a tunable, you will need to edit this file, and add the tunable name, together with its value, on a new line at the end of the file. After editting the file, you will need to restart the Load Balancer before the changes take effect. (Run ZEUSHOME/restart-zeus)

Each Load Balancer has it's own global.cfg file, so if you have a pair of balancers you will need to edit the configuration file on both machines. While this means slightly more work to add tunables, it does allow you to have unique settings for each balancer, e.g. if they are installed on different systems that may benefit from different tuning values.

Content Manager [Administrator] 12 August 2005