Moving accounts without disruption.
WHY IT HAPPENS
Hardware replacement Rebalancing load Upgrading the platform Consolidating or splitting
WHAT TO PLAN
What moves, and in what order How long each takes What the fallback is How customers are informed
WHAT TO DO ABOUT NAME RESOLUTION
Lower the time-to-live well in advance.
WHY
So the change takes effect quickly once made.
WHAT THE STANDARD SEQUENCE IS
Copy the account Synchronise changes since the copy Freeze changes briefly Final synchronisation Switch the destination Verify Keep the old copy until certain
WHAT TO VERIFY AFTERWARDS
Sites load Mail sends and receives Databases are complete Scheduled tasks run Certificates are present and valid
WHAT PEOPLE FORGET
Scheduled tasks Certificates Custom configuration Mail still arriving at the old server during propagation
WHAT TO DO ABOUT THAT LAST POINT
Keep the old server accepting and forwarding mail until propagation completes.
WHAT TO COMMUNICATE
When, what may be affected, and what the customer must do, if anything.
