zfs discuss - Mar 2008 - Mount order of ZFS filesystems vs. other filesystems?

I seem to be having a problem mounting the filesystems on my machine, 
and I suspect it''s due to the order of processing of /etc/vfstab vs.
ZFS
mount properties.

I have a UFS /export, then I have a ZFS that mounts on /export/OSImages.
In that ZFS I have a couple of directories with many .ISO files.

In /etc/vfstab, I have entries that mount the ISO''s using LOFI onto 
mountpoints which are also located under /export/OSImages.

All of these mounts are failing at bootup with messages about 
non-existent mountpoints. My guess is that it''s because when
/etc/vfstab
is running, the ZFS ''/export/OSImages'' isn''t mounted
yet?

Any ideas?

After bootup, I can login and run ''mountall'' manually and
everything
mounts just fine.

 -Kyle

Hello Kyle!

> All of these mounts are failing at bootup with messages about
> non-existent mountpoints. My guess is that it''s because when
/etc/vfstab
> is running, the ZFS ''/export/OSImages'' isn''t
mounted yet?
Yes, that is absolutely correct.  For details, look at the start method
of svc:/system/filesystem/local:default, which lives in the script
/lib/svc/method/fs-local.  There you can see that ZFS is processed
after the vfstab.
> Any ideas?
The only way I could find was to set the mountpoint of the file system
to legacy, and add it to /etc/vfstab.  Here''s an example:

  # ZFS legacy mounts:
  SHELOB/var - /var zfs - yes -
  SHELOB/opt - /opt zfs - yes -
  SHELOB/home - /home zfs - yes -
  #
  # -- loopback mount -- begin
  # loopback mount for /usr/local:
  /opt/local - /usr/local    lofs - yes ro,nodevices
  /home/cvs - /opt/local/cvs lofs - yes rw,nodevices
  # -- loopback mount -- end

Before I added /home to vfstab, the loopback for /opt/local/cvs would
fail.


HTH -- Volker
-- 
------------------------------------------------------------------------
Volker A. Brandt                  Consulting and Support for Sun Solaris
Brandt & Brandt Computer GmbH                   WWW: http://www.bb-c.de/
Am Wiesenpfad 6, 53340 Meckenheim                     Email: vab at bb-c.de
Handelsregister: Amtsgericht Bonn, HRB 10513              Schuhgr??e: 45
Gesch?ftsf?hrer: Rainer J. H. Brandt und Volker A. Brandt

Volker A. Brandt wrote:
> Hello Kyle!
>
>
>   
>> All of these mounts are failing at bootup with messages about
>> non-existent mountpoints. My guess is that it''s because when
/etc/vfstab
>> is running, the ZFS ''/export/OSImages'' isn''t
mounted yet?
>>     
>
> Yes, that is absolutely correct.  For details, look at the start method
> of svc:/system/filesystem/local:default, which lives in the script
> /lib/svc/method/fs-local.  There you can see that ZFS is processed
> after the vfstab.
>
>   
Ok. So my theory was right. :)
>> Any ideas?
>>     
>
> The only way I could find was to set the mountpoint of the file system
> to legacy, and add it to /etc/vfstab.  Here''s an example:
>
>   
I tried this last night also, after sending the message and I made it 
work. Seems clunky though.

I wonder if there is a technical reason why it has to be done in this order?

More importantly, I wonder if ZFS Boot will re-order this since the 
other FS''s will all be ZFS.
(Actually I wonder what will be left in /etc/vfstab?)
>   # ZFS legacy mounts:
>   SHELOB/var - /var zfs - yes -
>   SHELOB/opt - /opt zfs - yes -
>   SHELOB/home - /home zfs - yes -
>   #
>   # -- loopback mount -- begin
>   # loopback mount for /usr/local:
>   /opt/local - /usr/local    lofs - yes ro,nodevices
>   /home/cvs - /opt/local/cvs lofs - yes rw,nodevices
>   # -- loopback mount -- end
>
> Before I added /home to vfstab, the loopback for /opt/local/cvs would
> fail.
>
>
>   
I''m guessing that /opt/local/cvs is *not* visible as /usr/local/cvs ???

  -Kyle
> HTH -- Volker
>

> > The only way I could find was to set the mountpoint of the file system
> > to legacy, and add it to /etc/vfstab.  Here''s an example:
>
> I tried this last night also, after sending the message and I made it
> work. Seems clunky though.
Yes, I also would have liked something more streamlined.  But since adding
entries to vfstab worked I did not pursue if further.
> I wonder if there is a technical reason why it has to be done in this
order?
I can only guess that anything else would have been too complex.
The whole sequence seems to have room for improvement.  For example
in svc:/system/filesystem/root:default there are some checks to mount
optimized libc and hwcap libraries, and /usr is mounted, but not the
root fs (which I would have expected going by the FMRI name).
> More importantly, I wonder if ZFS Boot will re-order this since the
> other FS''s will all be ZFS.
My guess is that the whole thing will be rewritten.
> (Actually I wonder what will be left in /etc/vfstab?)
Good question.  I would think that the file will still be around; it''ll
have all the non-ZFS mount points, but the root fs will be mounted by
ZFS.
> >   # ZFS legacy mounts:
> >   SHELOB/var - /var zfs - yes -
> >   SHELOB/opt - /opt zfs - yes -
> >   SHELOB/home - /home zfs - yes -
> >   #
> >   # -- loopback mount -- begin
> >   # loopback mount for /usr/local:
> >   /opt/local - /usr/local    lofs - yes ro,nodevices
> >   /home/cvs - /opt/local/cvs lofs - yes rw,nodevices
> >   # -- loopback mount -- end
> >
> > Before I added /home to vfstab, the loopback for /opt/local/cvs would
> > fail.
>
> I''m guessing that /opt/local/cvs is *not* visible as
/usr/local/cvs ???
Oh, but it is:

  <shelob:/usr/local/cvs,3764# pwd
  /usr/local/cvs
  <shelob:/usr/local/cvs,3765# ls
  CVSROOT  bbc      pkg      rjhb     vab
  <shelob:/usr/local/cvs,3766# df .
  Filesystem            kbytes    used   avail capacity  Mounted on
  SHELOB/home          916586496 74753216 426294318    15%    /home
  <shelob:/usr/local/cvs,3767# mount | egrep
''local|cvs|home''
  /home on SHELOB/home read/write/setuid/devices/exec/xattr/atime/dev=4010004 on
Tue Mar 25 18:45:08 2008
  /usr/local on /opt/local read only/setuid/nodevices/dev=4010003 on Tue Mar 25
18:45:08 2008
  /opt/local/cvs on /home/cvs read/write/setuid/nodevices/dev=4010004 on Tue Mar
25 18:45:08 2008

:-)


Regards -- Volker
-- 
------------------------------------------------------------------------
Volker A. Brandt                  Consulting and Support for Sun Solaris
Brandt & Brandt Computer GmbH                   WWW: http://www.bb-c.de/
Am Wiesenpfad 6, 53340 Meckenheim                     Email: vab at bb-c.de
Handelsregister: Amtsgericht Bonn, HRB 10513              Schuhgr??e: 45
Gesch?ftsf?hrer: Rainer J. H. Brandt und Volker A. Brandt