2 Advanced GSLB configuration for IPv6

<weight> is a value from 0 to 100. The default value is 1. A weight of 0 implies that the client IP will not be allocated any hash buckets. A weight of 0 can be used to designate a domain IP as backup.

NOTE

The aggregate of the hash weights for all the IPs for a domain does not have to add up to 100.

When user configures a hash weight of zero for a domain IP, no hash buckets are allocated to this domain IP. If the hash buckets for this domain does not have any other healthy IPs, then the best IP address among all the healthy IPs including the IP with hash weight of zero, will be selected based on the remaining GSLB metrics. So user can configure a domain IP to be used as a backup IP by configuring a weight of zero for this IP address.

Disabling rehash on introduction of new IP addresses or state change from down to healthy

You can disable rehash on the introduction of a new IP address or change of IP address state from down to healthy. Persistence that occurs when rehashing is performed is prevented. The trade-off is the new IP address will not be included in the hash table.

To disable rehash, enter commands such as the following:

SLB-ServerIronADX(config)# gslb policy SLB-ServerIronADX(config-gslb-policy)# hash-persist persist-rehash-disable

Syntax: hash-persist persist-rehash-disable <time-out>

The <time-out>parameter specifies the number of seconds before an IP address is removed from the hash table when that IP becomes down. The default is five seconds.

Disabling rehash when weight for an IP is changed

When user changes the hash weight configured for an IP in the domain, GSLB controller will automatically rehash the hash table for that domain. You can disable this rehash on weight configuration change with the following command.

Use the following command line interface to disable rehashing on weight change for global GSLB policy:

ServerIronADX(config)# gslb policy

ServerIronADX(config-gslb-policy)# hash-persist disable-weight-rehash

Use the following command line interface to disable rehashing on weight change for host-level GSLB policy:

ServerIronADX# config t ServerIronADX(config)# gslb-host-policy test

ServerIronADX(config-gslb-host-policy-test)# hash-persist disable-weight-rehash

Syntax: [no] hash-persist disable-weight-rehash

If the weight of an IP for a domain is changed and this command is configured, then a message, stating that the ServerIron ADX needs to be rehashed at a later time, will be displayed.

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Brocade Communications Systems 12.4.00 manual Disabling rehash when weight for an IP is changed