Brocade Communications Systems 12.4.00 manual Configuring weights for domain IP addresses

Advanced GSLB configuration for IPv6 2

ServerIronADX(config)# gslb policy

ServerIronADX(config-gslb-policy)# hash-persist weighted

To enable weighted hash-based GSLB persistence for a host-level policy, enter commands on the GSLB controller, such as the following:

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

ServerIronADX(config-gslb-host-policy-test)# hash-persist weighted

Syntax: [no] hash-persist [weighted]

NOTE

Note that weighted is an optional parameter. If "weighted" is not specified, then the old hash-based persistence mechanism will be in effect. The old hash-based persistence mechanism distributes the hash buckets in a round robin manner. If the mechanism is changed from hash-based persistence to weighted hash-based persistence or vice versa in a GSLB global or host-level policy, then the hash table for all domains associated with that policy will be rehashed.

GSLB hash-based persistence with configurable subnet mask length

ServerIron ADX allows specification of subnet mask while doing GSLB site persistence. The LB controller hashes the entire 32-bits of a LDNS IP address to generate the hash bucket for GSLB hash-based persistence. As a result, LDNS servers in the same subnet could be assigned to different hash buckets. We now provide a mechanism for the user to define a subnet length for hashing; only this portion of the LDNS IP address will be used to generate the hash bucket. As a result, user can ensure that all the LDNS servers that fall in the same subnet, as defined by the hash prefix length, will hash to the same bucket and be serviced by the same domain IP address. As an example, if the specified source subnet mask is /24 then all LDNS servers within a given /24 subnet would receive same response (site IP) from the GSLB controller.

ServerIronADX(config)# gslb policy ServerIronADX(config-gslb-policy)# prefix-len-hash-persist 24

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

NOTE

This command should be configured under the GSLB global or host-level policy.

Configuring weights for domain IP addresses

Weighted hash-based persistence enables the user to distribute the hash buckets for the domain in proportion to the weights configured for the domain IP addresses. Use the following command line interface to configure weights for the domain IP addresses:

ServerIronADX(config)# gslb dns zone gslb.com ServerIronADX(config-gslb-dns-gslb.com)# host www http ServerIronADX(config-gslb-dns-gslb.com)# host www ip-hash-weight 2001:db8::10 ServerIronADX(config-gslb-dns-gslb.com)# host www ip-hash-weight 2001:db8::40

Syntax: host-info <host-name>ip-hash-weight <IPaddress> <weight>

•The <host-name>parameter specifies the host name.

•<IP address> is the IP address for which you are assigning a hash weight.

ServerIron ADX Global Server Load Balancing Guide	227
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