I migrated a site from one platform to another. In the process, the site went down with a 404 not found error from Apache. When the Migrate task completed, Apache (not Drupal) still threw a 404 error. Post 8080 (Apache, behind Varnish) delivered the page. So I restarted varnish and the site began responding again on port 80.
Hmmm... Should Varnish be restarted as part of the Migrate task? Why have I never experienced this with any other Migrate tasks?