ServerIron ADX Global Server Load Balancing Guide 227
53-1002437-01
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 par ameter. If "weig hted" 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 rou nd 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.