How content moves from the old CMS to the new one
Drupal's Migrate API treats migration as an Extract, Transform, Load (ETL) process. In Drupal the three ETL phases are called source, process and destination. Three practical rules apply:
Order. Migrations have an order: for example, Drupal migrates users before the content nodes that reference them.
Embedded files. URLs of embedded content such as videos, images, JavaScript and CSS files must be moved like any other content.
Import. Google lists setting up the CMS and importing the content from the old site as a typical step in preparing the new site.
Google's site-move guide prefers one change at a time, such as the domain first and the CMS or layout later; for how fields and content types survive the move, see why structured data matters in a CMS migration.
Why content migration is more than an export
Audit first. Content should be audited before an automated migration so outdated or unnecessary pages are not moved.
Budget manual work. Iowa expects few, if any, sites to have all content migrated automatically, so manual work must be budgeted.
Map the URLs. Google says it is important to map each old URL to its URL on the new site.
Freeze content. In Acquia's plan, content freezes later than code, shortly before the final migration, and the freeze lasts until final testing ends and the DNS switch is done.
For a CMS-to-CMS example, see migrating from Contentful to Sanity.
Launch-day content at Pagepro
Pagepro unpublishes pages that are not content-ready on launch day instead of moving the date. Those pages return a 404 and go live as their content lands.
Sources
- Content Migration (Digital Experience training)State of Iowa, Department of Management (public-sector guidance) · dxtraining.iowa.gov
- Set Up Content Migration FrameworkContentstack (platform documentation) · contentstack.com
- Migrate API overviewDrupal.org (platform documentation) · drupal.org
- Site Moves and MigrationsGoogle · developers.google.com
- Assisted migration engagementAcquia (platform documentation) · docs.acquia.com