Brocade Communications Systems 12.4.00 Manual De Usuario
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ServerIron ADX Global Server Load Balancing Guide
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Advanced GSLB configuration for IPv6
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If GSLB default location is not specified and if the requesting client prefix is from an unknown
geography, then the GSLB controller assigns "north-america" as its geography. However, if the
default location is specified, the GSLB controller assigns the configured geography to unknown
client prefixes.
geography, then the GSLB controller assigns "north-america" as its geography. However, if the
default location is specified, the GSLB controller assigns the configured geography to unknown
client prefixes.
NOTE
This command requires a reload to take effect; therefore, always issue the write memory command
after configuring the command.
after configuring the command.
Enabling default geographic location
The use-default-location command enables you to ensure that the geographic policy metric is used
to load balance client requests even if the client prefix cache maintained by the GSLB ServerIron
ADX is full.
to load balance client requests even if the client prefix cache maintained by the GSLB ServerIron
ADX is full.
By default, the GSLB ServerIron ADX ignores the default location of new client requests if its client
prefix cache if full. Whenever the GSLB ServerIron ADX cannot create a new entry in the client
prefix cache because it has already exceeded the limit, it ignores the geographic policy metric and
falls to the next metric in the GSLB policy.
prefix cache if full. Whenever the GSLB ServerIron ADX cannot create a new entry in the client
prefix cache because it has already exceeded the limit, it ignores the geographic policy metric and
falls to the next metric in the GSLB policy.
If the use-default-location command is configured for either the global GSLB policy or the host-level
GSLB policy, the ServerIron ADX uses the default location of the client and the geographic policy
metric when determining how to distribute the client’s request.
GSLB policy, the ServerIron ADX uses the default location of the client and the geographic policy
metric when determining how to distribute the client’s request.
To ensure that the geographic policy metric is used, enter commands such as the following:
ServerIronADX(config)# gslb policy
ServerIronADX(config-gslb-policy)# use-default-location
The default location of the client corresponds to the default location configured on the GSLB
controller. If no default location is configured on the GSLB controller, then n-america is assigned by
default. For more information, see
controller. If no default location is configured on the GSLB controller, then n-america is assigned by
default. For more information, see
To view geographic policy metric settings see
Available session capacity metric
If multiple sites are equal after the above comparisons, the GSLB ServerIron ADX prefers the site
ServerIron ADX (remote ServerIron ADX) whose session table has the most unused entries.
ServerIron ADX (remote ServerIron ADX) whose session table has the most unused entries.
When comparing sites based on the session table utilization, the GSLB ServerIron ADX considers
the sites to be equal if the difference in session table utilization does not exceed the tolerance
percentage. The tolerance percentage ensures that minor differences in utilization do not cause
frequent, and unnecessary, changes in site preference.
the sites to be equal if the difference in session table utilization does not exceed the tolerance
percentage. The tolerance percentage ensures that minor differences in utilization do not cause
frequent, and unnecessary, changes in site preference.
For example, suppose one ServerIron ADX has 1 million sessions available, and another has
800,000 sessions available. Also assume that the tolerance is 10% (the default). In this case the
first ServerIron ADX (with 1 million sessions available) is preferred over the second ServerIron ADX
because the difference (200,000) is greater than 10% of 1 million. If a third ServerIron ADX has
950,000 sessions available, that ServerIron ADX is equally preferable with the first ServerIron ADX
(with 1 million sessions available), because the difference in percentage between the available
sessions on the two ServerIron ADXs is only 5%, which is less than the tolerance threshold.
800,000 sessions available. Also assume that the tolerance is 10% (the default). In this case the
first ServerIron ADX (with 1 million sessions available) is preferred over the second ServerIron ADX
because the difference (200,000) is greater than 10% of 1 million. If a third ServerIron ADX has
950,000 sessions available, that ServerIron ADX is equally preferable with the first ServerIron ADX
(with 1 million sessions available), because the difference in percentage between the available
sessions on the two ServerIron ADXs is only 5%, which is less than the tolerance threshold.
You can change the following parameters associated with the session-table metrics: