Brocade Communications Systems ServerIron ADX 12.4.00 - Manual (Page 238)

226 ServerIron ADX Global Server Load Balancing Guide
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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

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
“Clearing GSLB phash counters” on page 246.
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: