Database gone away = duplicate ticket

[Pilky]

Hi,

When I shutdown MySQL or if the backup of the database is running (with mysqldump), OTRS duplicate a lots of tickets.
I decided to add a lock file in the crontab to pass "$HOME/bin/PostMasterMailbox.pl". Because I don't want to fetch email when backup is running but this morning, some 4000 tickets were duplicated !

I have the same trouble if the database was stopped.

I have the 2.4.7 version (yes, it's old).

Thanks for your help !