GTM Upgrade FAIL - DC Links & ICMP Monitors

So no monitor traffic, eh? That's a tough one to diagnose without knowing more about your environment. A couple things come to mind:

 

 

* Long monitor Interval: In my experience, it takes a few minutes for the LTM/GTM to initialize its network interfaces. If you have a long monitor Interval, it's possible that the GTMD process attempted the monitor ping before the network interfaces were initialized. You simply took the tcpdump before the next Interval. If it's large, perhaps try dropping the interval down to something like 10 seconds temporarily before running tcpdump. Seems very unlikely that TMM would have such a major flaw that would cause it to not send monitor traffic at all.

 

 

* I've seen upgrades (admittedly, in the v4 -> v9 days) move the VLAN from untagged to tagged, and our switches weren't configured for it. This caused complete network outage until we moved the interfaces back to untagged.

 

 

* Interface speed/duplex changes - perhaps double-check these interface properties, or even more basic, verify the interfaces weren't disabled during the upgrade?

 

 

Those are the things I would be checking first.