GTM Topo Failure

Try this config. I think this will do what you want:

1. NY pool. LB methods preferred: RR, alternate: none, fallback: none
2. Phx pool.LB methods preferred: RR, alternate: your_choice, fallback: your_choice
3. Assign pools to wideip. Wideip LB method: topology
4. Custom topology region containing NA, SA, Oceania
5. Topology record NA,SA,O > NY pool, weight 100
6. Topology record: NA,SA,O > Phx pool, weight 50
7. GTM will select the matching record with the highest weight (NY pool) but if all NY members are unavailable and alt/fallback LB methods=none it will then move on to a matching record with a lower weight (Phx pool).
8. When NY is available again name resolution will resume to NY but you can set manual resume on the NY pool so GTM doesn't switch back automatically.