What is the Logic of VS Status behavior when using multi pool selection by iRules or Local Trafic Policy?

Hi everebody,

 

I want to understand logic of VS Health Status because it used by GTM or Monitoring System (like Spectrum or SCOM).

 

Real Example:

 

I have the Application (actually, my client have many similar apps :), which depends of two different pools. I have 2 Datacenters with L3 connectivity. Because of this, I need to use 2 instances of Application on each Datacenter for DR. I need one global Wide IP and 2 VS on each DC. Moreover, when one of pools on each DC is down I need failover Wide IP to Second DC.

 

As I understand the algorithm (ver 13.): 1.Using iRule – VS Status is Up until at least one of the pools (including Default Pool) is UP. 2.Using Traffic Policy – VS Status only depends of Default Pool.

 

Refer to this link https://devcentral.f5.com/questions/mark-an-ltm-virtual-down-when-pool-in-an-irule-is-down there are only hard methods to implement this (VS come down If at least one of the pools is Down): 1) add External monitor 2) using iCall.

 

Please explain to me correct behavior and tell me any news to achieve the goal by using simple method (Big-IP web GUI :).