zfs discuss - Oct 2010 - Space not freed from large deleted sparse file

I created a 1TB file on my new FreeNAS 0.7.2 Sabanda (revision 5226)
box recently using dd, in order to get an idea of write performance,
and when I deleted it the space was not freed.

Snapshots are not enabled:
    bunker:~# zfs list -t all
    NAME    USED  AVAIL  REFER  MOUNTPOINT
    tank0  1.99T   707G  1.99T  /mnt/tank0

    bunker:~# zfs list -t snapshot
    no datasets available

And there should be almost exactly 1TB used, not 1.99TB:

    bunker:/mnt/tank0# zfs list
    NAME    USED  AVAIL  REFER  MOUNTPOINT
    tank0  1.99T   707G  1.99T  /mnt/tank0

(I put 1TB of data on it, then created this 1TB file, so I know this for sure)

I removed the file using a simple rm /mnt/tank0/temp/mytempfile.bin.
It''s definitely gone. But the space hasn''t been freed.

I have been pointed in the direction of this bug
http://bugs.opensolaris.org/view_bug.do?bug_id=6792701
which appears to be in ZFS version 14, and my FreeNAS distro is at
version 13. Is this the issue?

I would really appreciate some help with this. The FreeNAS forums and
documentation haven''t been any help.

Thanks in advance.

-- 
Tom Fanning

Hi all

I''m reposting this since I don''t know if the first one made it
to the list.

I created a sparse 1TB file box recently using dd from /dev/zero, in
order to get a rough idea of write performance, and when I deleted it
the space was not freed.

This is on a raidz1, 4x1TB SATA drives.

Snapshots are not enabled:
   bunker:~# zfs list -t all
   NAME    USED  AVAIL  REFER  MOUNTPOINT
   tank0  1.99T   707G  1.99T  /mnt/tank0

   bunker:~# zfs list -t snapshot
   no datasets available

And there should be almost exactly 1TB used, not 1.99TB:

   bunker:/mnt/tank0# zfs list
   NAME    USED  AVAIL  REFER  MOUNTPOINT
   tank0  1.99T   707G  1.99T  /mnt/tank0

(I put 1TB of "real" data on it, then created this 1TB file, so I know
this for sure)

I removed the file using a simple rm /mnt/tank0/temp/mytempfile.bin.
It''s definitely gone. But the space hasn''t been freed.

I have been pointed in the direction of this bug
http://bugs.opensolaris.org/view_bug.do?bug_id=6792701

which appears to be in ZFS version 14, and my FreeNAS distro is at
version 13. Could this be the issue? If so, what is the correct course
of action? Ditch FreeNAS and move to a distro with a more recent ZFS
version? If I do this, is it safe to upgrade my ZFS version knowing
that there is something up with the filesystem?

I would really appreciate some help with this. The FreeNAS forums and
documentation haven''t really been much help, and I created this file
on a live filesystem with data on it, so I''m 1TB down and not sure
what I can do.

Thanks in advance.
Tom

>I removed the file using a simple rm /mnt/tank0/temp/mytempfile.bin.
>It''s definitely gone. But the space hasn''t been freed.
>
>I have been pointed in the direction of this bug
>http://bugs.opensolaris.org/view_bug.do?bug_id=6792701
It was apparently introduced in build 94 and at that time we had a zpool
version of 11.
>which appears to be in ZFS version 14, and my FreeNAS distro is at
>version 13. Could this be the issue? If so, what is the correct course
>of action? Ditch FreeNAS and move to a distro with a more recent ZFS
>version? If I do this, is it safe to upgrade my ZFS version knowing
>that there is something up with the filesystem?
I believe it will just work.


Casper

>>I removed the file using a simple rm /mnt/tank0/temp/mytempfile.bin.
>>It''s definitely gone. But the space hasn''t been freed.
>>
>>I have been pointed in the direction of this bug
>>http://bugs.opensolaris.org/view_bug.do?bug_id=6792701
>
> It was apparently introduced in build 94 and at that time we had a zpool
> version of 11.
Can you confirm that "Fixed In: snv_118" means the issue was fixed in
ZFS pool version 17?
http://hub.opensolaris.org/bin/view/Community+Group+zfs/17
>>which appears to be in ZFS version 14, and my FreeNAS distro is at
>>version 13. Could this be the issue? If so, what is the correct course
>>of action? Ditch FreeNAS and move to a distro with a more recent ZFS
>>version? If I do this, is it safe to upgrade my ZFS version knowing
>>that there is something up with the filesystem?
>
> I believe it will just work.
Sorry, that what will just work? Moving to a distro with more recent
ZFS support and upgrading my pool?

Thanks
Tom

>>>I removed the file using a simple rm /mnt/tank0/temp/mytempfile.bin.
>>>It''s definitely gone. But the space hasn''t been
freed.
>>>
>>>I have been pointed in the direction of this bug
>>>http://bugs.opensolaris.org/view_bug.do?bug_id=6792701
>>
>> It was apparently introduced in build 94 and at that time we had a
zpool
>> version of 11.
>
>Can you confirm that "Fixed In: snv_118" means the issue was fixed
in
>ZFS pool version 17?
>http://hub.opensolaris.org/bin/view/Community+Group+zfs/17
The version of zpool changes only when there''s a change to the on-disk
format.  It was fixed in build 118 but no change was made to the
zfs version.  zpool version was bumped in build 120.
>>>which appears to be in ZFS version 14, and my FreeNAS distro is at
>>>version 13. Could this be the issue? If so, what is the correct
course
>>>of action? Ditch FreeNAS and move to a distro with a more recent ZFS
>>>version? If I do this, is it safe to upgrade my ZFS version knowing
>>>that there is something up with the filesystem?
>>
>> I believe it will just work.
>
>Sorry, that what will just work? Moving to a distro with more recent
>ZFS support and upgrading my pool?

Even without the upgrade but I''m not sure.

Casper