A while back we promised an article on namespace planning and load balancing principles with Exchange 2013. We’re finally going to fulfill that promise as a series of articles. The articles will s...
Updated Jul 01, 2019
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In your recommended Unbounded model, you show a single DAG in an Active/Active configuration. Since there is only 1 File Share Witness active at a time, how are you ensuring the DAG servers in the datacenter w/o the FSW are able to maintain quorum in the event of WAN communication issues? It seems to me that any time the WAN goes out for more than a few seconds the DAG nodes in the non-FSW datacenter will go terminate Exchange (to prevent an Exchange split-brain scenario).
At the moment that's why a single Active/Passive DAG is more attractive to me, with the "bound" model where all client requests go to the Active datacenter. I'm hoping there is something new in Exchange 2013 that allows a DAG to run Active/Active w/o having the cluster service bring down Exchange on the DAG nodes in the non-FSW datacenter just because of WAN connectivity issues. Otherwise I'm having a hard time understanding how this model can provide the HA an Active/Passive model can.
At the moment that's why a single Active/Passive DAG is more attractive to me, with the "bound" model where all client requests go to the Active datacenter. I'm hoping there is something new in Exchange 2013 that allows a DAG to run Active/Active w/o having the cluster service bring down Exchange on the DAG nodes in the non-FSW datacenter just because of WAN connectivity issues. Otherwise I'm having a hard time understanding how this model can provide the HA an Active/Passive model can.