This is a factor that I didn't cover in my original reply. There's some additional information that is created as a result of SQL Backup Pro's backup and restore information, that we need to store. For eg, the compression and encryption levels; the status of copy-to activities; locations of log files; the log copy queue for network resilience and for upload to the hosted storage service; the results of scheduled backup verification activities; etc.

We do duplicate some of the basic data that's stored in the msdb database, for eg, some of the data from the backuphistory table. One reason for this is that there may be shorter retention periods on these tables than is set for SQL Backup Pro's history.

Hope this helps,

Colin.