Hello Vincenzo Ferrarese,
Please check below log files:
For ABAP stack upgrades:
SUM/abap/tmp - written FIRST here than move to SUM/abap/log
SUM/abap/log - AFTER SUM completed
For JAVA stack upgrades:
/usr/sap/SUM/java/log
/usr/sap/SUM/java/trc
For further troubleshooting tips, you can also refer to the SAP System Upgrade & Update Troubleshooting Wiki Space:
http://wiki.scn.sap.com/wiki/display/SL/System+Upgrade+And+Update
Best regards,
James
