i know that Microsoft SQL Server nowhere documents that it is safe, correct, valid, or intended to backup the data (.mdf) and log (.ldf) files (*while SQL Server is running). i.e. you have no idea what state those files are in – they're not your files.
Some backup software claims to be able to backup SQL Server data&log files while they are in use.
Nevermind the fact if it (happens) to work – is it intended behavior?
Best Answer
Yes, it is valid IF (!) the program fully integrates into the backup AP's that windows offers. Basically they TELL SQL Server to bring the files int oa consistent state and then the file is snapshotte. The term is VSS (Volume Shadow Copy) and there is an API for that. SQL Server supports it.