Improving migration performance

Migrating large volumes of data can take considerable time - hours, or if you're migrating millions of objects, days. Shaving a few milliseconds off each item migrated can save you substantial time in the long run. Here are some hints and resources to help you turn those migrations around more quickly.

1. Disable hooks or modules during migration
2. Run migrations in Drush rather than the UI
3. Tune your database
4. Identify bottlenecks
5. Disable hooks during migration (Drupal 7)
6. Use highwater marks to identify changed content
7. Multi-processing with Drush