I really like webmin, but I have found what I think is a really serious issue. I am using Webmin 1.610 towards Ubuntu 12.04 Server and Mysql 5.5.28.
I have a few databases that use the AUTO_INCREMENT feature of SQL on one of the fields. I backup databases regularly using Webmin and thought everything was OK. However I was fored to use the backups after a disk failure and I discovered that Webmin does not seem to handle the AUTO_INCREMENT property correctly and I have seen two different instances. The first is where the AUTO_INC is just ignored and not part of the field properties in the backup. The second is a bit trickier and occurs such that the AUTO_INC property is set, but the AUTO_INCREMENT value is set to the last row to the table. So if the table had 5000 rows, the AUTO_INC value will be 5000 instead of 1.
Has anybody else seen this?