Hello,

We just had a serious issue with ZLB. To summarize, no Aliases VIP was 
able to reach its default gateway. The gateway was however reachable 
using the physical IP or the CARP VIP.
Analyzing the logs i've seen that there were a flapping. The standby 
decided to go Master and then switched back to standby afterward.

# On the Master
Aug  2 13:00:20 VMWZLB001 ucarp[1141]: [WARNING] Non-preferred master 
advertising: reasserting control of VIP with another gratuitous arp
Aug  2 13:00:20 VMWZLB001 ucarp[1141]: [WARNING] Non-preferred master 
advertising: reasserting control of VIP with another gratuitous arp
Aug  2 13:00:20 VMWZLB001 ucarp[1141]: [WARNING] Non-preferred master 
advertising: reasserting control of VIP with another gratuitous arp

# On the Slave
Aug  2 13:00:16 VMWZLB002 ucarp[1073]: [WARNING] Switching to state: MASTER
Aug  2 13:00:16 VMWZLB002 ucarp[1073]: [WARNING] Spawning 
[/usr/local/zenloadbalancer/app/zenlatency/zenlatency-start.pl eth0 
192.168.135.240]
Aug  2 13:00:28 VMWZLB002 ucarp[1073]: [WARNING] Switching to state: BACKUP
Aug  2 13:00:28 VMWZLB002 ucarp[1073]: [WARNING] Spawning 
[/usr/local/zenloadbalancer/app/zenlatency/zenlatency-stop.pl eth0 
192.168.135.240]
Aug  2 13:00:33 VMWZLB002 ucarp[1073]: [WARNING] Preferred master 
advertised: going back to BACKUP state

The result was that the physical and CARP VIP was still working, but the 
VIP used in farms were not working. I'm not exacly sure why, perhaps 
because they became UP at 2 location at the same time and the Zen and/or 
Switch/Router did not like that fast flapping. I believe the CARP VIP 
continued to work because it's actively sending gratuitous arp, but the 
other aliases not?

My questions are:
- Is it possible (I believe yes but I have not found where yet) to 
change the deadratio and/or advertisement interval of carp so it's less 
sensitive ? And would you advice it?
- Is it possible to send gratuitous arp also for the Aliases used in farms ?

Thanks a lot
tibz

ps: Emilio i've applied your farmgardian patch, will see in the coming 
days how it goes ;-)

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