Hello,
I have this plesk and OS versions:
CentOS Linux 7.2.1511 (Core)
Versión de Plesk 12.5.30 Actualización #29, última actualización 19/Abr/2016 03:50
I can t use backup, either update plesk.
So, in order to debug my problem i found vg-00-usr 10 gb was full, so i increased with 2gb...