Different sizes between zfs list and zpool list

[Freddie Cash]

On Wed, May 5, 2010 at 9:20 AM, Tom Evans <tevans.uk at googlemail.com> wrote:

> On Wed, May 5, 2010 at 4:56 PM, Freddie Cash <fjwcash at gmail.com> wrote:
> > On Wed, May 5, 2010 at 8:44 AM, Tom Evans <tevans.uk at googlemail.com>
> wrote:
> >
> >> When looking at the size of a pool, this information can be got from
> >> both zpool list and zfs list:
> >>
> >> > $ zfs list
> >> NAME                       USED  AVAIL  REFER  MOUNTPOINT
> >> tank                      5.69T   982G  36.5K  /tank
> >>
> >> > $ zpool list
> >> NAME   SIZE   USED  AVAIL    CAP  HEALTH  ALTROOT
> >> tank  8.14T  6.86T  1.28T    84%  ONLINE  -
> >>
> >> Why the different sizes?
> >> The pool is a raidz of 6 x 1.5 TB drives.
> >>
> >
> > zpool lists the raw storage available to the pool.  Every single bit of
> > every single drive is listed here.  This will be 6 x 1 TB.
> >
> > zfs lists only the amount of storage available to be used, after all
> > redundancy is taken into account.  This will be 5 x 1 TB.
>
> Ah, that makes sense - also explains why the df output matches up
> precisely with the zfs list output.
>

Things get really interesting once you enable compression on a filesystem,
as then du, df, and zfs list will all be different.  :)

There's a great post on the zfs-discuss mailing list that covers this.  I'll
see if I can dig it up.

-- 
Freddie Cash
fjwcash at gmail.com