Hello, I am trying to migrate from the existing 2 node cluster 2008R2( data center A) to 4 node always on 2017 ( Node 1 and Node2( Data center B) and (Node3, node4) are in Data center C. Synchrnous between N1 and N2 and asynchrnous N3,N4), Looking for shortest downtime possible the databases size is close to 8 TB Thanks