Hi, Oliver,
If you want to overwrite the backup devide, you need to use the INIT option. Please see the description about the INIT option in MSDN.
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{ NOINIT | INIT } Controls whether the backup operation appends to or overwrites the existing backup sets on the backup media. The default is to append to the most recent backup set on the media (NOINIT).NOINIT Indicates that the backup set is appended to the specified media set, preserving existing backup sets. If a media password is defined for the media set, the password must be supplied. NOINIT is the default.INIT
Specifies that all backup sets should be overwritten, but preserves the media header. If INIT is specified, any existing backup set on that device is overwritten, if conditions permit. By default, BACKUP checks for the following conditions and does not overwrite the backup media if either condition exists:
--Any backup set has not yet expired. For more information, see the EXPIREDATE and RETAINDAYS options.
--The backup set name given in the BACKUP statement, if provided, does not match the name on the backup media. For more information, see the NAME option, earlier in this section.
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DB13 uses the stored procedure sap_backup_database to execute the backup command. The default is INIT. But please check SAP KBA 1867938. There is an error happening if you use only one media to do the backup on DB13 with init option and expiration date.
Best regards.
Cherry