Re: deduplicating file systems: VDO with Debian?

[Dan Ritter <dsr@randomstring.org>]

didier gaumet wrote: 
> 
> I may be mistaken, but I think there is a confusion here about a
> deduplication at filesystem level and at backup tool level.
> 
> At (linux) filesystem level, I think in-line deduplication is only provided
> by ZFS (and perhaps, out-of-tree, BTRFS)

ZFS deduplication is a special beast that usually does not make
people happy. It is an enterprise feature that really only works
for special cases, and requires a lot of RAM - 1GB per 1TB of
storage - to work. Worst of all, it cannot be gracefully turned
off.

As you say, deduplication in backup systems is quite common, and works
pretty well. There's also an on-disk non-filesystem utility, rdfind,
which is packaged in Debian. It can discover identical files and make
them hardlinks.

-dsr-