On windows 2008 R2 we use windows backup to backup the SQL Server database files while SQL Service is running. (The SQL Server database files were not excluded.) In the error log of SQL Server we found entries like:
... I/O is frozen on database master. No user action is required. However, if I/O is not resumed promptly, you could cancel the backup.
... I/O was resumed on database master. No user action is required.
I understand these entries showing that the ntbackup with VSS-Service, SQL Writer Service and SQL Server works correctly. The database files are backup in a consistent state.
Doing the same on Windows 7 (with running SQL Server) we could _not_ find any similar entry in the SQL Server error log mentioned above after backup has finished.
We are now unsure that the database files are backup in a consistent state with Windows 7 backup while SQL Service is running.