How long does a migration usually take

The copying is usually the short part. A single ordinary site is often moved and testable within a few hours. What decides the calendar is DNS and how many sites are involved, not how long files take to transfer.

A realistic shape for one site

• Copying: minutes to a few hours, depending on size. Databases and stored mail take longer than files.
• Testing before DNS: as long as you want. The old site is still live, so this costs nothing but your time.
• DNS propagation: from minutes to a day, decided by the TTL that was in place before you changed anything.
• Watching afterwards: a day or two of checking logs and mail.

So the file copy might be an hour and the whole thing still spans three days. That is normal and it is not waiting on us.

What actually makes it longer

• A high TTL. A record cached for 24 hours means some visitors keep reaching the old server for a day after you switch. Lowering TTL a day or two ahead is the single most effective thing you can do, as described in how long DNS changes take.
• Large mailboxes. Years of stored mail can take longer than the entire website.
• Sites nobody documented. Time goes on working out what a site needs, not on moving it.
• Waiting on someone else for registrar or DNS access.

Many sites at once

An estate does not multiply cleanly. Twenty sites is not twenty times one site, because the copying overlaps but the checking does not. In practice the constraint is how many sites a person can verify properly in a day.

Moving in waves is almost always faster in wall clock terms than attempting everything in one night, because a problem found in wave one is fixed before it repeats nineteen times. That approach is set out in sequencing a multi site migration.

The part with no downtime

Everything up to the DNS change happens while your sites keep running on the old host. Nothing is switched until you decide. That means a migration can be prepared over a week at whatever pace suits you, and the actual cutover is short.

Our checklist for the moment before a domain is repointed lists what to confirm first. If you have a fixed date, tell us at the start rather than partway through so the sequence can be planned backwards from it.