Mektozo , Just another Contoso ! :)

I faced a very strange case with Exchange DAG, I was doing a site resiliency test I failed over to the DR site successfully and then I failed back to the main site, after failing back I found that the DAG was in a state that looks like split brain syndrome although the DAG was running in DAC mode. the symptoms were as follows: From the DR mailbox server: Cluster Console only showed this node while the active nodes were not present. From EMC the copies on the DR server were healthy. From the Main site mailbox servers: Cluster console showed the three nodes but the DR node was stopped, and the option to start it was grayed out. From EMC the copies on the DR server were failed. The fix was as follows:  run the following command: Cluster       /forcecleanup Then run the following: Start-DatabaseAvailabilityGroup "DAGname" -MailboxServer  "DRNodeName" After the first command you will find that the DR node can see the oth...

While I was working on a DAG with separate MAPI and Replication Networks whenever I  make any changes to DAG like running start-DatabaseAvailabilityGroup or Set-DatabaseAvailabilityGroup I get the following warning message: "No static address matched networks "Cluster Network ". Specified static addresses: x.x.x.x". The Cluster Network was the Replication Network whose subnet is different than that of the DAG IP addresses. Seems that Exchange wanted to utilize this network for MAPI traffic. Although When I run the command get-DatabaseAvailabilityGroupNetwork I find that MAPIEnabled is false on the replication network. when I compared the cluster networks of this DAG with another healthy DAG I found that the checkbox "allow clients to connect through this network" was checked. when I uncheck it, it gets checked by itself again  !. The reason was that one of the DAG members had the "register this connection's address in dns" che...