How We Migrated 30 WordPress Sites to a New Server Overnight

An agency client had outgrown their ageing server: 30 live WordPress sites, all sluggish, all on a box that was running out of road. They needed everything moved to new infrastructure without their clients noticing. We did it in one overnight window.

The risk with multi-site migrations

It’s not one migration — it’s 30 chances for something to go wrong: a missed database, a hard-coded URL, a broken cron job, an SSL certificate that doesn’t follow. The key is a repeatable process applied identically to every site.

Our approach

1. Inventory and audit every site: PHP version, plugins, database size, cron jobs and certificates.
2. Build the new server to match or exceed the old stack, hardened and monitored from day one.
3. Pre-sync all files with rsync days in advance, so the cutover only moves what changed.
4. Lower DNS TTLs ahead of time so the switch propagates fast.

The overnight cutover

# Final delta sync of files — only what changed since the pre-sync
rsync -aHz --delete /old/sites/ newserver:/var/www/sites/

# Per-site database export/import, then a safe URL search-replace
wp search-replace 'http://old' 'https://new' --all-tables

We migrated databases site by site, ran a careful search-replace to fix any hard-coded URLs, reissued SSL certificates, and tested each site against the new server using a hosts override before flipping DNS.

Verify, then switch

Only once every site rendered correctly on the new box did we cut DNS over. We kept the old server untouched for a week as a rollback safety net. The result: 30 faster sites, zero data loss, and clients who never knew it happened.

Big migrations feel scary because they’re usually done in a rush. Done as a rehearsed, checklist-driven process, they’re just careful, methodical work.

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