I have a 4 Tb SQL Server 2008 R2 database. I'm going to move this DB to a new server with a new release of SQL Server 2012. (the application does not support SQL Server > 2012, but that is not the subject of my question).
Before that, I'm going to move almost all objects from the main datafile of 4To to multiple datafiles on the same filegroup so I can get back the free space on the 4Tb file.
After moving objects, free space take like forever to be reclaimed with a dbcc shrink file with blocs of 256Mo.
What's the fastest way to get that space back to the OS?
Is there a way to use a backup restore to shrink the file?