differential backup question

[geo2500]

Hi,
I have this question.
When you do a differential backup, how does SQL-Server find out what was the last complete backup in order to do the diff backup?
If I do them automatically then it knows, but if I do them manually and in different folders how does it know?
Thanks,
George

 

[mrdenny]

When you do a backup of the SQL Server is logs the backup in the msdb database. I'm pretty sure it's msdb.

Denny

--Anything is possible. All it takes is a little research. (Me)

 

[RonPro]

Plug this in to your BOL search field

Differential Changed Map

Basically, what it says is that SQLServer maintains a map of the pages that have been changed since *THE* last complete backup was performed. IOW - you can make any number of differential backups in different folders, but they will all only reflect changes made to the DB since the last full backup - whoever made it and wherever it resides.