Date: Wed, 5 May 2010 09:08:08 -0700 From: Jeremy Chadwick <freebsd@jdc.parodius.com> To: Tom Evans <tevans.uk@googlemail.com> Cc: FreeBSD Stable <freebsd-stable@freebsd.org> Subject: Re: Different sizes between zfs list and zpool list Message-ID: <20100505160808.GA69687@icarus.home.lan> In-Reply-To: <20100505155833.GA69377@icarus.home.lan> References: <AANLkTim-yHHl9Neeb40gD3W333foqEIcGYCY2EaorvKg@mail.gmail.com> <20100505155833.GA69377@icarus.home.lan>
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On Wed, May 05, 2010 at 08:58:33AM -0700, Jeremy Chadwick wrote:
> On Wed, May 05, 2010 at 04:44:32PM +0100, Tom Evans 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.
>
> Is the tank filesystem using compression? "zfs get all" would help shed
> some light here.
>
> There is some variance in AVAIL on all of our systems, and I see
> identical on Solaris 10. My guess is (the equivalent of) parity of
> raidz has something to do with it.
>
> However, in the case of our systems, USED always matches between zfs
> list and zpool list.
I should have provided some actual sample data to back this up. I only
checked one of our systems, which uses mirror. Here's a better sample
set. Some of these use the 'quota' property, but none use compression.
host1$ zfs list
NAME USED AVAIL REFER MOUNTPOINT
data 4.49G 681G 18K none
data/home 793M 681G 793M /home
data/storage 3.72G 681G 3.72G /storage
host1$ zpool list
NAME SIZE USED AVAIL CAP HEALTH ALTROOT
data 696G 4.49G 692G 0% ONLINE -
host1$ zpool status
...
NAME STATE READ WRITE CKSUM
data ONLINE 0 0 0
ad6 ONLINE 0 0 0
host2$ zfs list
NAME USED AVAIL REFER MOUNTPOINT
data 312G 1.48T 24.0K none
data/backups 312G 1.48T 312G /backups
data/home 48.0K 256G 48.0K /home
host2$ zpool list
NAME SIZE USED AVAIL CAP HEALTH ALTROOT
data 2.72T 469G 2.26T 16% ONLINE -
host2$ zpool status
...
NAME STATE READ WRITE CKSUM
data ONLINE 0 0 0
raidz1 ONLINE 0 0 0
ada1 ONLINE 0 0 0
ada2 ONLINE 0 0 0
ada3 ONLINE 0 0 0
host3$ zfs list
NAME USED AVAIL REFER MOUNTPOINT
pool 45.5G 175G 45.4G /home
host3$ zpool list
NAME SIZE USED AVAIL CAP HEALTH ALTROOT
pool 224G 45.5G 179G 20% ONLINE -
host3$ zpool status
...
NAME STATE READ WRITE CKSUM
pool ONLINE 0 0 0
mirror ONLINE 0 0 0
ad4s1g ONLINE 0 0 0
ad6 ONLINE 0 0 0
host4$ zfs list
NAME USED AVAIL REFER MOUNTPOINT
data 250G 664G 18K none
data/cvs 299K 8.00G 299K /cvs
data/home 643M 15.4G 643M /home
data/storage 249G 664G 249G /storage
host4$ zpool list
NAME SIZE USED AVAIL CAP HEALTH ALTROOT
data 928G 250G 678G 26% ONLINE -
host4$ zpool status
...
NAME STATE READ WRITE CKSUM
data ONLINE 0 0 0
mirror ONLINE 0 0 0
ada1 ONLINE 0 0 0
ada2 ONLINE 0 0 0
So in summary, Freddie's explanation sounds spot on.
--
| Jeremy Chadwick jdc@parodius.com |
| Parodius Networking http://www.parodius.com/ |
| UNIX Systems Administrator Mountain View, CA, USA |
| Making life hard for others since 1977. PGP: 4BD6C0CB |
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