Question on Topology Load Balancing

Hello Devlin,

One other option to consider could be the following. Basically having your primary pool perform topology based load balancing and a last resort pool to handle queries that don't fall within your topology based rulesets.

WideIP:

    gtm wideip www.application.com {
    last-resort-pool www.application.com-round_robin
    pool-lb-mode topology
    pools {
        www.application.com-topology { }
    }

Primary Pool:

gtm pool www.application.com-topology {
alternate-mode global-availability
load-balancing-mode topology
members {
    10.1.1.1:443 {
        order 1
        vs-name www.application.com-10.1.1.1
    }
    10.2.2.2:443 {
        vs-name www.application.com-10.2.2.2
    }
}

Last Resort Pool:

gtm pool www.application.com-round_robin {
members {
    10.1.1.1:443 {
        order 1
        vs-name www.application.com-10.1.1.1
    }
    10.2.2.2:443 {
        vs-name www.application.com-10.2.2.2
    }
}

Virtual in DC1:

gtm server LTM-DC1 {
addresses {
    10.10.10.10 { }
}
datacenter "DC1"
monitor bigip
virtual-servers {
    10.1.1.1:443 {
        name www.application.com-10.1.1.1
    }
}

Virtual in DC2

gtm server LTM-DC2 {
addresses {
    10.20.20.20 { }
}
datacenter "DC2"
monitor bigip
virtual-servers {
    10.2.2.2:443 {
        name www.application.com-10.2.2.2
    }
}

Topology Rulesets:

gtm topology  ldns: subnet 10.30.30.0/24  server: datacenter "DC1" { }
gtm topology  ldns: subnet 10.40.40.0/24  server: datacenter "DC2" { }