Configuring a Globally-Distributed Network
3-DNS® Administrator Guide 6 - 7
With this topology statement, in our example configuration, queries to
resolve www.siterequest.com from local DNS servers somewhere in North
America get responses from virtual servers in the pool americas_pool. All
other queries to resolve www.siterequest.com get responses from virtual
servers in the pool europe_pool.
Additional configuration settings and tools
The following optional settings and tools can help you refine your load
balancing configuration.

Setting limits thresholds

When you set limits thresholds for availability, the 3-DNS Controller can
detect when a managed server or virtual server is low on system resources,
and can redirect the traffic to another virtual server. Setting limits helps
eliminate any negative impact on a virtual server's performance of service
tasks that may be time critical, require high bandwidth, or put high demand
on system resources. The system resources for which you can set limits are:
•CPU
•Disk
•Memory
Packet rate
Kilobytes per second (throughput rate)
Current connections

To set limits thresholds for BIG-IP systems

1. In the navigation pane, expand the Servers item, and click BIG-IP.
2. In the Limits Settings column of the BIG-IP system for which you
want to set limit thresholds, click the Configure Limits button .
The Modify Server Limits Settings screen opens.
3. Check the metrics for which you want to set limits, and type values
based on your network resources. For more information and help on
this screen, click Help on the toolbar.
You can also set limits thresholds on virtual server resources. Please note
that if a server meets or exceeds its limits settings, both the server and the
virtual servers it manages are marked as unavailable for load balancing. You
can quickly review the availability of any of your servers or virtual servers
in the Statistics screens in the Configuration utility.