[CentOS] block level changes at the file system level?

>
> Perhaps there is a file system that supports compression and would do a
> good job with the snapshots transparently.  Maybe even ZFS or btrfs do?
>

Hi,
I agree with Lee.
Btrfs actually does sport built-in compression as a mount argument/flag and
the delta snapshots works beautifully well but I wouldn't dare to use it
with any kernel previous to 3.13; in fact best practice would be to use it
with kernel 3.14.x or later, preferably 3.15.x and later.
B.R.