Configuring GSLB protocol parameters | 1 |
After changing policy values, you can display the new values using the show gslb policy command. If you decide you want to change a value back to its default (using “no” in front of the command you used to change it), you can display all the default policy values by entering the show gslb default command. Refer to “Displaying the default GSLB policy” on page 175.
NOTE
You also can configure the ServerIron ADX to intercept or directly respond to DNS queries instead of evaluating responses from the authoritative DNS server. Refer to “DNS cache proxy” on page 91 and “Transparent DNS query intercept” on page 95.
Changing the order of GSLB policy metrics
You can change the order in which the GSLB ServerIron ADX applies the policy metrics.
NOTE
We recommend that you always use the health check as the first metric. Otherwise, it is possible that the GSLB policy will not select a “best” choice, and thus send the DNS reply unchanged. For example, if the first metric is geographic location, and the DNS reply contains two sites, one in North America and the other in South America, for clients in South America the GSLB policy favors the South American site after the first comparison. However, if that site is down, the GSLB policy will find that none of the sites in the reply is the “best” one, and thus send the reply unchanged.
You cannot change the position of the least response selection or round robin selection metric, whichever is enabled. The GSLB ServerIron ADX uses the least response selection or round robin selection metric as a
To change the order, specify the metrics in the desired order, by entering a command such as the following:
ServerIronADX(config)# gslb policy
This command changes the GSLB policy to the following:
•The
•The
•The site ServerIron ADX’s session capacity threshold
•The site ServerIron ADX’s remote SI session capacity threshold
•The site ServerIron ADX’s FlashBack speed (how quickly the GSLB receives the health check results)
•The Least Response selection (the site ServerIron ADX that has been selected less often than others)
Two of the metrics, server health and geographic location, are not specified. As a result, these metrics are not used when evaluating site IP addresses in the DNS responses.
Syntax: [no] metric-order set <list>
The <list> parameter is a list of the metrics you want to use, in the order you want the GSLB ServerIron ADX to use them. The GSLB uses the metrics in the order you specify them. You can specify one or more of the following:
ServerIron ADX Global Server Load Balancing Guide | 37 |
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