Date: Sun, 15 Apr 2012 13:14:25 +0200 From: "Ronald Klop" <ronald-freebsd8@klop.yi.org> To: freebsd-fs@freebsd.org Subject: Re: ZFS and disk usage Message-ID: <op.wcsz6bcp8527sy@pinky> In-Reply-To: <jm9gkf$l16$1@dough.gmane.org> References: <4F8825E5.3040809@gmail.com> <1334323707.4f8829fbe801e@www.hyperdesktop.nl> <jm9gkf$l16$1@dough.gmane.org>
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On Fri, 13 Apr 2012 17:27:10 +0200, Johannes Totz <johannes@jo-t.de> wrote:
> On 13/04/2012 14:28, Mark Schouten wrote:
>> Hi,
>>
>> Op Vrijdag, 13-04-2012 om 15:11 schreef Volodymyr Kostyrko:
>>>> These are fiesystems that are created with the following
>>>> command. zfs create -V ${size}GB ${ZFS_ROOT}/${diskname}
>>>
>>> `zfs create -V` withous `-s` creates reserved volume that eats all
>>> needed space immediately. Technically zfs pool is filled only for
>>> 23%, but logically you have only 138G left unassigned.
>>
>> I understand. However, the created volumes should use a total of
>> 1211GB. That's not 1.6TB like zfs list says. But 1211 + 431
>> (referred) does come close to 1.6TB.n And 1.6 TB still isn't the
>> 1.77TB that's in the zpool.
>>
>> I have this feeling that zfs has reserved the space for each volume,
>> but counts data written to the volumes in usage of the main
>> filesystem. Mainly because zfs list shows me that the volumes have
>> only 16KB referenced, where /storage has 431GB referenced.
>
> Without checking the numbers myself...
> Note that zpool and zfs do not agree on (free) space accounting: zpool
> shows "raw" space, whereas zfs includes metadata overhead for itself.
>
> Small rant: I dont understand why zpool and zfs show different things.
> If you have an integrated storage stack then why not show consistent
> numbers? Is there any use for this extra (mis-)information that
> zpool-vs-zfs provides?
>
It isn't integrated that far as you might think. That is why you have
zpool and zfs tools. These are 2 separate things. You can also put a zvol
+ ufs or zvol + iscsi on the zpool and not use zfs. How would zpool know
about ufs or iscsi usage? Or how would ufs know about the underlying
zpool+zvol?
Ronald.
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