Cloud Migration Without Downtime — Is It Really Possible?
Clients often ask: "Do we have to migrate over the weekend?" The honest answer: no — if you approach it the right way. Here is how we do it.
Whenever we offer cloud migrations, one question almost always comes up: "When do we have to shut down?" The answer surprises many: in most cases — not at all.
Why the fear of downtime?
Classic migration approaches have a fixed cutover date: old systems off at 6 p.m. on Friday, new systems on at 10 p.m. on Sunday. That used to be the standard — and it still makes sense today for very simple scenarios.
But for modern migrations (Exchange → Microsoft 365, file server → SharePoint, on-prem ERP → Azure), there are far more elegant approaches.
The hybrid mode
The trick: the old and new worlds run in parallel during the transition phase. Specifically:
- •DNS-based routing: mail flow goes to both systems, new mailboxes live in the cloud system, old ones stay on-prem until they are migrated
- •Sync tools keep both systems in sync (e.g., Azure AD Connect for identities)
- •Stage by stage instead of big bang: move 10 users per week instead of everyone at once
Example: Microsoft 365 migration
In a typical project with 80 mailboxes:
- •Weeks 1–2: Set up the tenant, run the Hybrid Configuration Wizard, install Azure AD Connect
- •Week 3: Move pilot users (5–10 people from IT), test workflows
- •Weeks 4–7: Move 20 users per week in batches — in the evening, no user notices a thing
- •Week 8: Migrate the last mailboxes, shut down the old Exchange servers
Throughout all of this: no downtime for end users. Mail flow works, calendars work, Teams works.
What does the complexity cost?
Hybrid migrations take 1–2 weeks longer than a big bang. In return:
- •No weekend operation with pizza at 3 a.m.
- •If problems arise, you can roll back without data loss
- •We train users in parallel — no one is overwhelmed on Monday morning
When does the classic big-bang approach fit?
For very small setups (< 20 users), when functionality stays very similar, and when the IT department is experienced. Otherwise: go hybrid.
Our approach
We always start with a migration assessment (2 days). Afterwards, you know exactly:
- •Which data is moving
- •In what order
- •How long it will take
- •What you need to do to prepare
Fixed price from €1,800. If you have questions, get in touch.