Error running shared postrotate script for /var/log/mysql.log /var/log/mysql/mysql.log /var/log/mysql/mysql-slow.log

Una solució a aquest error és mirar el password que hi ha a /etc/mysql/debian.cnf i posar-lo a l'usuari debian-sys-maint a MySQL:

GRANT RELOAD, SHUTDOWN, PROCESS, SHOW DATABASES, SUPER, LOCK TABLES ON *.* TO 'debian-sys-maint'@'localhost' IDENTIFIED BY PASSWORD 'XXXXXX';