Plesk upgrade fail

Hello

I try to upgrade Plesk from v12.0.8 to 12.5.30 on a Centos 5.11 however the upgrade fail at the preupdate stage.

===> Upgrading database

Trying to start service mysqld... mysqld (pid 13595) is running...
done
Trying to establish test connection... connected
done
Trying to find psa database... version is 012000018
Trying to backup MySQL database... done
MySQL databases are dumped to /home/dumps/mysql.preupgrade.12.0.18-12.5.30.20160207-105541.dump.gz
Trying to allow INNODB...

Plesk upgrade fail