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NimbostratusSplitting HA across datacentres
Hi all,
We are looking at a typical datacentre design with geographically separated Production and DR datacentres, by ~100kms. Layer 2 connectivity is provided via 10Gb dark fibre so we have the option of cross-site VLANs to do HA.
Is there a limitation on doing HA across two boxes over 100kms apart? What is the best practice F5 architecture for such scenarios?
Thanks, CK
2 Replies
The only thing you really need to worry about as distances grow is the potential for split-brain situations (active-active) due to congestion or network latency.
I think many people already use F5 equipment in this kind of setup, as far as I know, you only really need to increase the Network Failover Timeout to account for the increased distance. The default is 3 seconds, which seems mighty enough for even your proposed distance, but I'd play it safe and raise this to 6 seconds.
tmsh modify sys db failover.nettimeoutsec value 6For anything else, just use the normal common-sense approach.
Wand_97484You could think about GTM (DNS) failover between your primary and desaster DC, if it is applicable for you.
