Hi,
You will find some information about backups, restoring and recovery on
the homepage of the Advanced Technology Group:
http://service.sap.com/atg
Backup and Restore for SAP System Landscapes
The ATG also provides the "SAP Continuity Management" service for
optimizing your backup and restore/recovery strategy.
The following are 2 general notes should be used for your reference:
842240 FAQ: Backup strategy of large and highly-available databases
605062 FAQ: Restore and recovery
Regards,
Aidan