File: //usr/share/webmin/virtual-server/help/config_single_tx.html
<header>Backup MySQL in a single transaction?</header>
When this option is set to <b>Yes</b>, MySQL backups will be performed in a
single transaction to ensure consistency. However, this can consume more RAM
when backing up a large and changing database. It can also fail with the
error <tt> Couldn't execute 'FLUSH TABLES WITH READ LOCK'</tt> on some MySQL
versions or Amazon RDS. In this case, you should change this to <b>No</b>
instead. <p>
<footer>