Changing the order of gslb policy metrics – Brocade Virtual ADX Global Server Load Balancing Guide (Supporting ADX v03.1.00) User Manual
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Brocade Virtual ADX Global Server Load Balancing Guide
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Configuring GSLB protocol parameters
1
NOTE
You also can configure the Brocade Virtual ADX to intercept or directly respond to DNS queries
instead of evaluating responses from the authoritative DNS server. Refer to
“Transparent DNS query intercept”
Changing the order of GSLB policy metrics
You can change the order in which the GSLB Brocade Virtual 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 Brocade Virtual ADX uses the Least Response Selection or Round
Robin Selection metric as a tie-breaker if the other comparisons do not result in selection of a “best”
site.
To change the order, specify the metrics in the desired order, by entering a command such as the
following.
Virtual ADX(config)#gslb policy
Virtual ADX(config-gslb-policy)#metric-order set health-check capacity
num-session flashback
This command changes the GSLB policy to the following:
•
The health-check results
•
The site ADX device’s session capacity threshold
•
The site ADX device’s remote SI session capacity threshold
•
The site ADX device’s FlashBack speed (how quickly the GSLB receives the health check
results)
•
The Least Response selection (the site ADX device 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 Brocade
Virtual ADX to use them. The GSLB uses the metrics in the order you specify them. You can specify
one or more of the following:
•
active bindings – The Brocade Virtual ADX’s preference for the IP address with the highest
number of active bindings.
•
capacity – The remote ADX session capacity threshold.
•
connection-load – The site ADX device’s average number of new connections per second