50 ServerIron ADX Global Server Load Balancing Guide
53-1002437-01
Configuring GSLB protocol parameters
1
ServerIronADX(config)# gslb policy
ServerIronADX(config-gslb-policy)# connection-load limit 500
This command sets the site connection limit to 500 connections. During site comparison, the GSLB
policy discards sites that have an average load of new connections that is higher than the amount
you specify. All other sites are passed to the next GSLB policy metric as potential candidates.
Syntax: [no] connection-load limit <average-load>
You can specify from 1 to as high a value as you need. There is no default. You must specify a
connection limit to enable the connection limit metric.
Changing the sampling intervals and sample rate
The sampling interval is the number of data samples the GSLB controller averages together to
calculate a site’s connection load. The sample rate is the number of seconds between intervals.
By default, each GSLB site takes five samples, at 5-second intervals. Using the default sampling
interval and sample rate, the site takes samples after 5 seconds, 10 seconds, 15 seconds, 20
seconds, and 25 seconds.
The number of new connections the site has at each of the five intervals is averaged together. This
average value is the one the GSLB controller uses for the comparison:
•You can specify from 1-8 sampling intervals. The default is 5.
•You can specify from 5-60 seconds for the sample rate. The default is 5 seconds.
At any given time, the average connection load for a site is the average of the latest full set of data
samples. For example, if the sampling interval is 5, then the average load is the average of the five
most recent samples.
NOTE
The accuracy of the average is affected by the initial sampling rate. For example, if the sampling rate
is 5 seconds, the average at the seventh second will consist of the average for the first through fifth
seconds, rather an average for the second through seventh seconds.
By default, the site ServerIron ADX samples the load of new connections every five seconds and
stores the average connection load for five intervals: the average loads at the previous 5, 10, 15,
20, and 25 seconds.
You can change the sampling interval and sample rate. Enter a command such as the following at
the GSLB policy level of the CLI.
ServerIronADX(config-gslb-policy)# connection-load intervals 6 5
This command changes the number of sampling intervals from 5 to 6 but leaves the sample rate
set to 5 seconds. At any given time, the site ServerIron ADX will have the average load for six
intervals, for the previous 5, 10, 15, 20, 25, and 30 seconds. The average connection load will be
calculated based on these six samples.
Syntax: [no] connection-load intervals <num-intervals> <sampling-rate>
The <num-intervals> parameter specifies the number of samples you want the site ServerIron ADX
to collect and average together. You can specify 1-8 intervals. The default is 5.
The <sampling-rate> parameter specifies the number of seconds between each sample. You can
specify 1-60 seconds. The default is 5 seconds.