Forum Discussion
Exchange 2016 DAG design
Lagged copies shouldn't be blocked, as the DAG can them promote them to regular copies should disk space require this (play down) or other circumstances like the lagged copy requiring page patching, or the number of copies falls below 3. This can be controlled using the DAG's ReplayLagManagerEnabled switch. Regarding (automatic) activation, using the best copy and server selection process, the activation preference is more of a tie-breaker rather than an indication of preference, as it is used when more than one copy is determined eligible for activation. The whole process is described in detail here: https://technet.microsoft.com/en-us/library/dd776123(v=exchg.160).aspx. If there is really a need to block lagged copies for activation, blocking them on server level or copy level is a possible option; I had a customer who - for all their reasons - wanted dedicated servers with lagged copies, and they put the AP=5 and AP=6 copies on those, and blocked activation on the server level .
Lagged copies shouldn't be blocked, as the DAG can them promote them to regular copies should disk space require this (play down) or other circumstances like the lagged copy requiring page patching, or the number of copies falls below 3. This can be controlled using the DAG's ReplayLagManagerEnabled switch. Regarding (automatic) activation, using the best copy and server selection process, the activation preference is more of a tie-breaker rather than an indication of preference, as it is used when more than one copy is determined eligible for activation. The whole process is described in detail here: https://technet.microsoft.com/en-us/library/dd776123(v=exchg.160).aspx. If there is really a need to block lagged copies for activation, blocking them on server level or copy level is a possible option; I had a customer who - for all their reasons - wanted dedicated servers with lagged copies, and they put the AP=5 and AP=6 copies on those, and blocked activation on the server level .
That article is exactly what I was looking for. It turns out I don't have to change anything. I assumed AP was the only parameter used in the decision, but now I've learned it is not.
Thx!
Sven