Specifications

Working with Geographic Clusters
Equalizer Installation and Administration Guide 155
Working with Geographic Clusters
This section shows you how to add or delete a geographic cluster and how to configure a
geographic cluster’s load-balancing options. Configuring a geographic cluster and its sites is
analogous to configuring a virtual cluster and its servers.
Adding a Geographic Cluster
To add a new geographic cluster, follow these steps:
1. Log into the Equalizer Administration Interface in edit mode.
2. Select Geographic Cluster from the Add menu in the main menu bar. The add geocluster
screen appears in the right frame (see Figure 74).
Figure 74 Add geocluster screen
3. Enter the geocluster name, which is the fully-qualified domain name (FQDN) of the
geographic cluster (for example,
www.coyotepoint.com). The FQDN must include all name
components up to the top level (com, net, org, etc). Do not include the trailing period.
4. Specify the responsiveness. This value controls how aggressively Equalizer adjusts the site’s
dynamic weights. Equalizer provides five response settings: Slowest, Slow, Medium, Fast, and
Fastest. Faster settings enable Equalizer to adjust its load balancing criteria more frequently and
permit a greater variance in the relative weights assigned to sites. Slower settings cause site
measurements to be averaged over a longer period of time before Equalizer applies them to the
cluster-wide load balancing; slower settings also tend to ignore spikes in cluster measurements
caused by intermittent network glitches. We recommend that you select the Medium setting as a
starting point.
5. Enter the
DNS cache ttl (cache time-to-live), which is the length of time, in seconds, that the
client’s DNS server should cache the resolved IP address. Longer times will result in increased
failover times in the event of a site failure, but are more efficient in terms of network resources.
A reasonable value would be 120 (that is, 2 minutes).
6. Enter the MX exchanger, which is the fully qualified domain name to be returned if Equalizer
receives a “mail exchanger” request for this geographic cluster. The mail exchanger is the host
responsible for handling email sent to users in the domain.
7. Specify the policy: