Database backups occur while the sites are still online

[gregharvey]

This should be fixed as a generic MySQL thing that applies to all build scripts, there should be no way we're ever backing up the database of an application that is not in offline (or readonly, if Drupal) mode, because of the risk of locking and the fact we're backing up volatile data.

[EmlynK]

This is in place for Drupal builds and has been for some time. Symfony is more difficult as there isn't really an offline mode (at least not one that is utilised during a Symfony build).