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Forum Discussion

jamesdris's avatar
jamesdris
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Mar 19, 2019

F5 DNS sync groups, datacenters and prober pools

I have a few questions - 1 - Can we have prober pools in a global availability mode? If yes does it mean when the primary listener is down the servers will be polled using the secondary prober on th...
application delivery
BIG-IP DNS
f5 dns sync group
prober pool
Rico_368208's avatar
Rico_368208
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Mar 19, 2019
  1. Yes, global availability can be configured and it just means it will use the first available member of the pool. You can see that in the Create a Prober Pool section of this article
  2. If no prober pool is configured, the BIG-IP DNS devices negotiate amongst themselves which DNS device is responsible for which server.
  3. If there is a discrepancy in DNS devices marking a device as up, it will choose the health monitor data from the BIG-IP DNS device assigned to that server.

If you have any more questions, I am sure I can help

 

Rico_368208's avatar
Rico_368208
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Mar 20, 2019

In your first situation server1 would be marked as up because the health statistics would come from GTM1. In your second scenario, as long as the GTM1 sees the server as down, it will be marked down. The GTM devices will choose a device in the same datacenter as the device that it is trying to monitor. Even if that healthcheck is incorrect, the monitor status from the device in the same datacenter is what will be used.