[BBLISA] Backing up sparse files ... VM's and TrueCrypt ... etc

[David Allan]

On Mon, 22 Feb 2010, Dean Anderson wrote:

> Indeed.  To do what you want (only send the 20k that changed), one needs
> a versioning filesystem to do that. Like AFS or NetApp's fs.  What you
> want to do is intimately related to the capability of the filesystem to
> track what blocks have changed. AFS, for example, keeps one version back
> as the 'backup fileset' and an AFS incremental backup takes only the
> blocks that are different from the backup fileset. NetApp keeps 10
> versions but I don't remember how the NetApp backup works. There are
> efforts in AFS to allow more versions.  I don't know of any other
> filesystems that keep version information. Ordinary filesystems (like
> FFS, EXT2,3, NTFS) don't keep track of what blocks have changed since
> the last backup.
>
> But your point should be well taken to FS implementors: We need
> versioning filesystems.

Agreed with this statement of the problem, and that it is a valuable thing 
to have.  The universe of applications for such an implementation is way 
beyond simple backup.

For the immediate problem, Ned, does the solution of ignoring the disk 
files on the host and running the backup job in the VM work for you?

Dave