[clug] lessfs vs. btier vs. dm-dedup?

[Robert Edwards]

On a topic slightly related to Steve's about rsync, I was wondering
if anyone has played with any of the various open-source data
de-duplication block devices?

I am wanting to make complete disk-image backups of a lab full of
Windows 7 machines (about 40), that I can then restore again en-masse.

I am planning to PXE boot each machine with a small Linux image that
simply writes the bit-image of the local disk across the network to a
(per-machine) file on a Linux server that has a filesystem mounted on a
de-duplicated block device. The de-duplication should detect identical
disk blocks from the Windows disk images and only keep one copy of each.

When it is time to restore, just do the opposite (write the bit-image
back again).

I am looking at dm-dedup, but it looks a little pre-production. Other
contenders are lessfs and btier (or even ZFS, I suppose).

Anyone played in this space before?

cheers,

Bob Edwards.