Just be carefull when you set priority group, The higher the number, the higher the priority, so a member with a priority of 3 has higher priority than a member with a priority of 1.
So you have to alternative:
Alternative 1: Priority Group Activation less than 1
In this case if you have if you have 2 Singapore servers fails, the load balancin will be done on all other not only jurrong server but the 2 remaining servers.
- singapore-node-1 --> 4 (fails)
- singapore-node-2 --> 4 (fails)
- singapore-node-3 --> 4
- singapore-node-4 --> 4
- jurrong-node-1 --> 3
- jurrong-node-2 --> 3
- jurrong-node-3 --> 3
- jurrong-node-4 --> 3
Alternative 1: Priority Group Activation less than 1
In this case if you have if you have 2 Singapore servers fails, the load balancing will be done only on jurrong server. and if there are problems on the jurong servers the lb will be donne on all availlable server.
- singapore-node-1 --> 4 (fails)
- singapore-node-2 --> 4 (fails)
- singapore-node-3 --> 2
- singapore-node-4 --> 2
- jurrong-node-1 --> 3
- jurrong-node-2 --> 3
- jurrong-node-3 --> 3
- jurrong-node-4 --> 3
For more info:
http://blog.rapidlinksnetworks.co.uk/f5-bigip-priority-group-activation/
Let me know if you need more details.
regards