Forum Discussion
mikand_61525
Jan 19, 2012Nimbostratus
Techgeeeg: I think hoolio just explained that.
Instead of relying on if the serial cable functions or not you can use various monitors to decide when the F5 unit should failover or not.
If you for example have this setup:
F5_1 -> switch1 -> server1
F5_2 -> switch2 -> server2
and then have cables between switch1 - switch2 you could end up with a situation where F5_1 is active but switch1 is broken. In this situation server1 cannot reach F5_1 nor F5_2 while server2 can reach F5_2 but for no good since this unit is still passive (and just ignores the packets).
If you now use some monitors to trigger the HA instead of the status of the serial cable you would see that F5_1 cant reach server1 nor server2, BUT... F5_2 can at least reach server2. So in this particular case I would prefer that F5_2 becomes active (and sends some snmp trap thats something bad happend since all redundancy is now lost for the moment).