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Mohanad's avatar
Mohanad
Icon for Cirrostratus rankCirrostratus
Oct 01, 2019
Solved

F5 BIG-IP's in Different Datacenters

Hi everyone   if i implemented this setup:         What will happen if both ha links are down, each F5 device will think he is the active unit? if yes, how to mitigate this issue?   ...
application delivery
BIG-IP
  • Hamish's avatar
    Hamish
    Oct 09, 2019

    If all your links are down, then you go split brain. But if all your links are down, then you have more problems than just the split brain BigIP.

     

    (Note that the way I usually do this is an HA pair in each DC (Or metropolitan DC pair). Then use GTM to provide global resilience).

     

    Regarding fancy devices not requiring your network to be up to prevent split brain. Why bother? You can always put in a path that would encompass the same links as the failover clustering using witness. You're not limited to just two links.

Greasy_Pretzel's avatar
Greasy_Pretzel
Ret. Employee

The link you have shared talks about ASM sync... https://devcentral.f5.com/s/articles/syncing-asm-waf-policies-between-f5-big-ips-in-different-datacenters-or-cloud-regions-32891

 

f5 recommends; 1) Dedicated VLAN for HA failover; in failover IP address list, you have the self IP

2) Add Management IP in the failover IP address list

 

Review K16049 for more information on how to limit failover disruptions.

 

With Load aware (or HA Order) configurations, if both links, HA and management are down, you will see A-A situation.

 

However, you could test HA Group.

Mohanad's avatar
Mohanad
Icon for Cirrostratus rankCirrostratus
Oct 31, 2019

Thank Gr3asy so much, i will read K16049