zfs discuss - Feb 2010 - ZFS compressed ration inconsistency

Probably I''m missing something here, but what I see on my system

zfs list -o used,ratio,compression,name export/home/user
89.6G  2.86x    gzip-4  export/home/user

cmsmaster ~ # du -hs /export/home/user/
90G     /export/home/user/

du -hsb /export/home/user/
380781942931    /export/home/user/

89.6G*2.86=256.26G is way too far from 354.63G reported by du.

What''s wrong?
-- 
This message posted from opensolaris.org

On 01 February, 2010 - antst sent me these 0,6K bytes:
> Probably I''m missing something here, but what I see on my system
> 
> zfs list -o used,ratio,compression,name export/home/user
> 89.6G  2.86x    gzip-4  export/home/user
> 
> cmsmaster ~ # du -hs /export/home/user/
> 90G     /export/home/user/
> 
> du -hsb /export/home/user/
> 380781942931    /export/home/user/
> 
> 89.6G*2.86=256.26G is way too far from 354.63G reported by du.
> 
> What''s wrong?
       -b, --bytes
              equivalent to `--apparent-size --block-size=1''

       --apparent-size
              print apparent sizes,  rather  than  disk  usage;

/Tomas
-- 
Tomas ?gren, stric at acc.umu.se, http://www.acc.umu.se/~stric/
|- Student at Computing Science, University of Ume?
`- Sysadmin at {cs,acc}.umu.se

I would expect to see uncompressed size by "--apparent-size".
And what I see much above uncompressed size obtained by multiplication of
compressed size and ratio.
In fact, apparent size is consistent with amount used by same set of files on
linux system. (I''m moving my home directories from linux server to OSOL
server). So I really thing that 355G is uncompressed size of data. Then why 
used*ratio gives me 256.26G ? Where is almost 100GB? :)
-- 
This message posted from opensolaris.org

I''m more than happy by the fact that data consumes even less physical
space on storage.
But I want to understand why and how. And want to know to what numbers I can
trust.
-- 
This message posted from opensolaris.org

antst <ant.starikov at gmail.com> writes:
> I''m more than happy by the fact that data consumes even less
physical
> space on storage.  But I want to understand why and how. And want to
> know to what numbers I can trust.
my guess is sparse files.

BTW, I think you should compare the size returned from "du -bx" with
"refer", not "used".  in this case it''s not
snapshots which makes the
difference, though.

-- 
Kjetil T. Homme
Redpill Linpro AS - Changing the game