Website Migration Between Servers

Site migration between servers without downtime

A move looks simple: copy the files, transfer the database, change DNS. The problems start in the details — and usually cost lost orders.

The core difficulty

Time passes between copying the database and switching DNS. Everything that appeared on the old server in that window — new orders, registrations, stock changes — is missing from the new one. And because DNS propagates differently across providers, some visitors keep reaching the old server for hours afterwards.

So the move is done in two stages: an unhurried preliminary copy, then a short final synchronisation at the moment of the switch.

What is included

• preparing the new server: compatible PHP version, required extensions, configuration;
• transferring files and the database;
• verification on the new server before the DNS switch;
• an SSL certificate on the new host;
• migrating scheduled tasks;
• the final sync and the switch;
• watching the logs on both servers after the move.

What usually gets forgotten

Scheduled tasks that keep running on the old server and writing to the old database. Mail, if it lives on the same server. File permissions — after copying as an administrator, directories become unwritable. External services with an IP address whitelist.