_SQL_CONVERT default mode can be set per instance to innodb (same as YES) or myisam.

This allows to define global (daily) db tables conversion default mode per Octopus instance. It is also possible to override it per site, as needed, with special, empty control files: sites/foo.com/modules/to-innodb.info or sites/foo.com/modules/to-myisam.info -- but if *both* control files exist, no conversion is run at all. Note that this conversion will run daily even if all tables have been already converted, so it will run OPTIMIZE on all tables, effectively.