Sync Tests

Hi Snizri , 
so you have one device group contains ( 3 devices in-synced ) >> 2 in the main side and 1 in DR side , Correct ? 

could you clarify what do you mean by ( DR Device is Disabled ). 
To Test Sync >> 
- Open the GUI for each device and make sure that all objects are synced. 

- If you want to test traffic , and when one of devices become down which device will handle user traffic : 
Go to traffic group , I assume you only have one traffic group ( which is the default one ) >>> and check the prefered order or ( HA order List ) here is the piece which control your next active device if the current Active down. 

Let we say it in examples in your scenario : 
you have : 
main site ( Bigip_1 " Current Active " , Bigip_2 " Standby" ) 
DR site    ( Bigip_3 "Standby" ). 

Go to traffic group >>> you will see two methods of managing failover or selecting which be Active device in failures. 

- First method : HA order List >> and in this method you order your devices . like this : 
Bigip_1 ( Active) 
Bigip_2
Bigip_3

if Bigip_1 failed , it will failover to Bigip_2 and Bigip_2 become the Active and handle traffic. 
if Bigip_1 & Bigip_2 failed >>> Bigip_3 will take the Active role in the device group and handle traffic an so on. 

- Second method : Load aware >> maybe this is not the widely used one , but it depends on some caculations related to appliance capacity or depending on the quantity of load in this appliance , So based on that will choose the Active device. 
Also Load aware method used when using a heterogeneous devices so it looks for the most powerful device has the most capacity when failover occure. 

For more info about that , Please and mandatory to read this article well : https://techdocs.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/bigip-device-service-clustering-admin-11-5-0/8.html 
to learn how to manage HA failover and which device should handle traffic. 

Let me know if I missed something , I hope that my comment helps you ! 🙂