Website migration without downtime: the copy-and-switch discipline

A migration is a copy and a switch, and the order of operations is the whole craft: prove the new home before the old one lets go.

What stops most companies from changing hosting is the fear of downtime, and the fear is managed by understanding the mechanism: a migration is a copy and then a switch. Nothing is rebuilt, nothing is gambled. The order of operations is the whole craft, and every famous migration horror story is that order executed in reverse.

The failures are familiar. Moving by re-doing instead of copying, so the new site is a reconstruction that silently drops pages, forms, and details nobody remembered. Switching the domain to the new server before the new server has proven itself, which is testing on your customers. Discovering after the switch that the backup was the only plan, and it had never been restored once. And mail breaking because the migration touched records it had no reason to touch, since mail shares the domain with the site.

The practice starts early: set up and fully test the new server while the old one still serves. Copy, do not re-create. Then test the copy against real material, not a glance at the homepage: the forms, the checkout, the images, the deep pages nobody visits, which are exactly the ones that break quietly.

The switch itself is the smallest step if the preparation was honest. Keep both servers running through the change, and touch only what the switch requires: the records that point visitors at the new home. Nothing else on the domain needs to move, and anything else that moves is a mistake looking for a place to happen.

Two neighbours need watching. Mail shares the domain, and its records are separate: a website migration has no business altering them, and a company that watches its mail through the window after the switch catches a mistake in hours instead of weeks. And the old server stays warm for a defined window before it is closed, because visitors and systems that cached the old address will still knock there.

We run migrations on this sequence as part of our technical work, and we hand you guidance rather than guarantees: the mechanics of the switch belong to whoever operates your site and its records, read from their current documentation. Two essays sit beside this one and cover the neighbours: mail has its own move with its own sequence, and the restore test that proves the backup belongs before any of this starts.