Brocade Communications Systems ServerIron ADX 12.4.00 Manuale Utente

Advanced GSLB configuration for IPv6

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To create site persistence for a specific group (subnet) of clients, configure a different hash-based 
persistence prefix length for that group. Once configured, the GSLB controller will ensure that DNS 
clients within the same subnet will be served the same IP address in the GSLB response so long as 
the IP address belongs to the domain and is active.

To specify the prefix length, enter commands such as the following:

ServerIronADX(config)#gslb policy 

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ServerIronADX(config-gslb-policy)# ipv6-prefix-len-hash-persist 64

Syntax: [no] ipv6-prefix-len-hash-persist <decimal > 

The ipv6-prefix-len-hash-persist parameter specifies the hash-based persistence prefix length of 
IPv6 DNS clients. The parameter enables you to aggregate DNS clients to go to one domain IP. The 
default prefix length is 128 bits.

Manually forcing a rehash for a domain

The clear gslb ipv6 phash command enables you to clear the hash tables related to IPv6 
addresses.

To force a rehash of a persistent GSLB table, enter a command such as the following:

ServerIronADX# clear gslb ipv6 phash table all

Syntax: clear gslb ipv6 phash table [all | zone-name <zone-name> host-name <host-name>]

Use the clear gslb ipv6 phash counter command to clear GSLB phash counters. For more 
information see 

Weighted hash-based persistence for IPv6

Weighted hash-based persistence allocates the hash buckets in a weighted round robin fashion, 
enabling you to not only maintain persistence, but also determine what percentage of the traffic 
goes to a particular domain IP address. 

With weighted hash-based persistence, you can define hash weights for the IPs in a domain. The 
hash buckets are distributed among the domain IP addresses in proportion to these weights.

NOTE

All of the commands used to configure hash-based persistence IPv6 are also applicable to weighted 
hash based persistence. 

Enabling weighted hash-based GSLB persistence 

Weighted hash-based GSLB persistence can be enabled for all domains or for specific domains as 
needed. You can enable weighted hash-based persistence as the global or host-level policy. As a 
result, this feature applies to all the domains this policy is bound to. 

NOTE
Weighted hash-based persistence cannot be enabled concurrently with sticky persistence in the 
same policy. However, you can enable sticky persistence for one policy and weighted hash-based 
persistence for another policy. 

To enable weighted hash-based persistence globally, enter commands on the GSLB controller, such 
as the following: