How to accelerate backup for a BIG Files servers and SQL servers.

I have 3 very big fileserver, more than one billions of files.

Presently we using the MS-Windows policies to backup'em. I was reading that I could use the FLASHBACK policie (block level) for that kind of file server.

So if i'm using this kind of policie, should I use the FLASHBACK or the FLASHBACK-WINDOWS policie if my server is a windows 2008?

I dont fully understand the difference between MS-Windows, Flashbackup, Flashbackup-Windows.

We using flashbackup-windows to backup our VM on ESX server.

thanks