Implementing the active bindings metric – Brocade Communications Systems ServerIron ADX 12.4.00 User Manual
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ServerIron ADX Global Server Load Balancing Guide
53-1002437-01
Configuring GSLB protocol parameters
1
The second example shows the third site.
SITE: THREE
* a.b.c
DNS Requests: 36
ServerIronADX VIP Selection (%)
== === =============
1.1.1.3 1.1.1.183 0 (0 %)
Site Selection for Domain: 0 (0 %)
* b.b.c
DNS Requests: 0
ServerIronADX VIP Selection (%)
== === =============
1.1.1.3 1.1.1.123 0 (0 %)
Site Selection for Domain: 0 (0 %)
In the above examples, there are two hosts; a (HTTP) and b (FTP) which belong to the zone b.c.
There are three sites as listed below:
•
Local (weight: 50; ServerIron ADX: 1.1.1.1; VIPs: 1.1.1.180 (HTTP), 1.1.1.181 (HTTP), 1.1.1.121
(FTP)
•
TWO (weight: 50; ServerIron ADX: 1.1.1.2; VIPs: 1.1.1.182 (HTTP), 1.1.1.122 (FTP))
•
THREE (weight: 0; ServerIron ADX: 1.1.1.3; VIPs: 1.1.1.183 (HTTP), 1.1.1.123 (FTP))
The IP resolution for the domain names is as follows:
•
a.b.c.: 1.1.1.180; 1.1.1.181; 1.1.1.182
•
b.b.c.: 1.1.1.121; 1.1.1.122
After making 36 requests for domain "a.b.c.", the distribution was:
•
Site Local got 18 requests (VIP 1.1.1.180 received 9 and VIP 1.1.1.181 received 9)
•
Site TWO got 18 requests (VIP 1.1.1.182 received all 18)
•
Site THREE did not receive any requests because its weight is zero
Implementing the active bindings metric
You can configure a ServerIron ADX to prefer an IP address with the highest number of active
bindings.
Active bindings are a measure of the number of active real servers bound to a Virtual IP address
(VIP) residing on a GSLB site. The GSLB ServerIron ADX uses the active bindings metric to select
the best IP address for the client. The VIP with the highest number of active bindings is the IP
address preferred by the active bindings metric.
In order to implement the active bindings metric, the GSLB ServerIron ADX processes information it
receives from an agent. For each VIP address on the agent ServerIron ADX, the agent reports the
following information to the GSLB ServerIron ADX:
•
The virtual ports configured
•
The number of active real servers bound to the virtual port