Comment 9 for bug 839306

Let's document that on prepare either "innobackupex --apply-log" should be used which will read InnoDB configuration from backup-my.cnf automatically, or --defaults-file=backup-my.cnf should be passed to the xtrabackup binary if it is used to prepare.

This will be fixed when we merge innobackupex and xtrabackup into a single executable (or implement the mentioned blueprint).