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Forum Discussion

Baseline's avatar
Baseline
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Jun 29, 2017

Is there a GLB back off timer for failed pools

Hi, I've been searching and testing this for a couple of days but not been able to work it out, wondering if anyone knows.....?   I am testing GLB with topology based LB. There are 2 pools and all...
application delivery
BIG-IP DNS
Baseline's avatar
Baseline
Icon for Nimbostratus rankNimbostratus
Jun 29, 2017

I think I may have just stumbled across my own answer. If I look in DNS > GSLB > Wide IPs and then choose the Wide IP I'm interested. Under Pools it has Persistence = Yes with a TTL of 3600.

 

My assumption is that it will keep all traffic going to the second pool until the TTL timer expires? Presumably the TTL timer resets to 3600 each time it receives traffic so the client will have to send no traffic to the GTM for 1 hour before it will start using its preferred pool again.

 

If so, is the client the end user, or the user's local DNS server? If it's the local DNS server, in our scenario (we're a 24x7 business) the timer will rarely get to 0. Therefore, it's probably best for persistence to be turned off, or lowered to 1 or 2 mins?