zfs discuss - Mar 2010 - " . . formatted using older on-disk format . ."

Running b133

When you see this line in a `zpool status'' report:

  status: The pool is formatted using an older on-disk format.  The
        pool can still be used, but some features are unavailable.

Is it safe and effective to heed the advice given in next line:

  action: Upgrade the pool using ''zpool upgrade''.  Once this
is done,
        the pool will no longer be accessible on older software
        versions.

I don''t recall now what all I might have done when the disks were
installed. I do remember that they were new WD 750GB sata drives and
were set up as a mirror, maybe 6 to 9 mnths ago..

I was then, and still am bumbling around with only rudimentary
knowledge of what I''m doing or what needs doing.
(There has been some knowledge improvement in those 6-9 mnts [I hope])
 
I don''t think I really did any formatting at all.

This host is a home NAS and general zfs server.  It does not see
industrial strength use.  The hardware is older athlon64 (+3400)
with 3 GB ram.

What I''d like to learn from posting this, is if I should follow the
advice or am I likely to cause a pile of new problems.  Far as I know
this hasn''t caused problems so far.  Although there was a problem with
data corruption in 2 files....on this pool.  

In fact I just finished cleaning up two cases of data corruption in 2
files.  (now deleted, followed by a new scrub)

-------        ---------       ---=---       ---------      -------- 
Full status output:

  pool: z3
 state: ONLINE
status: The pool is formatted using an older on-disk format.  The pool can
        still be used, but some features are unavailable.
action: Upgrade the pool using ''zpool upgrade''.  Once this is
done, the
        pool will no longer be accessible on older software versions.
 scrub: scrub completed after 0h49m with 0 errors on Wed Mar 10 12:55:48 2010
config:

        NAME        STATE     READ WRITE CKSUM
        z3          ONLINE       0     0     0
          mirror-0  ONLINE       0     0     0
            c5d0    ONLINE       0     0     0  512K repaired
            c6d0    ONLINE       0     0     0  640K repaired

errors: No known data errors

On 03/11/10 03:21 PM, Harry Putnam wrote:
> Running b133
>
> When you see this line in a `zpool status'' report:
>
>    status: The pool is formatted using an older on-disk format.  The
>          pool can still be used, but some features are unavailable.
>
> Is it safe and effective to heed the advice given in next line:
>
>    action: Upgrade the pool using ''zpool upgrade''.  Once
this is done,
>          the pool will no longer be accessible on older software
>          versions.
>
>    
Yes, noting the warning.  So if you upgrade your root pool, you might 
not be able to boot a previous BE.
> I don''t recall now what all I might have done when the disks were
> installed. I do remember that they were new WD 750GB sata drives and
> were set up as a mirror, maybe 6 to 9 mnths ago..
>
> I was then, and still am bumbling around with only rudimentary
> knowledge of what I''m doing or what needs doing.
> (There has been some knowledge improvement in those 6-9 mnts [I hope])
>
> I don''t think I really did any formatting at all.
>
>    
It''s the pool format that changes, not the disk format.  Another 
overloaded and potentially confusing term!

-- 
Ian.

On Mar 10, 2010, at 6:30 PM, Ian Collins wrote:
> Yes, noting the warning.  
Is it safe to execute on a live, active pool?

--m

Matt Cowger wrote:
> On Mar 10, 2010, at 6:30 PM, Ian Collins wrote:
>
>   
>> Yes, noting the warning.  
>>     
>
> Is it safe to execute on a live, active pool?
>
> --m
>   
Yes.  No reboot necessary.

The Warning only applies to this circumstance:  if you''ve upgraded from
an older build, then upgrading the zpool /may/ mean that you will NOT be 
able to reboot to the OLDER build and still read the now-upgraded zpool.


So, say you''re currently on 111b (fresh 2009.06 build).   It has zpool 
version X (I''m too lazy to look up the actual version numbers now). 
You
now decide to live on the bleeding edge, and upgrade to build 133.  That 
has zpool version X+N.   Without doing anything, all pool are still at 
version X, and everything can be read by either BootEnvironment (BE).  
However, you want the neat features in zpool X+N.  You boot to the 133 
BE, and run ''zpool upgrade'' on all pools.  You now get all
those fancy
features, instantly.  Naturally, these new features don''t change any 
data that is already on the disk (it doesn''t somehow magically dedup 
previously written data).  HOWEVER, you are now in the situation where 
you CAN''T boot to the 111b BE, as that version doesn''t
understand the
new pool format.

Basically, it boils down to this:  upgrade your pools ONLY when you are 
sure the new BE is stable and working for you, and you have no desire to 
revert to the old pool.   I run a ''zpool upgrade'' right after
I do a
''beadm destroy <oldBE>''



-- 
Erik Trimble
Java System Support
Mailstop:  usca22-123
Phone:  x17195
Santa Clara, CA

On 11 Mar 2010, at 04:17, Erik Trimble wrote:
> Matt Cowger wrote:
>> On Mar 10, 2010, at 6:30 PM, Ian Collins wrote:
>> 
>>  
>>> Yes, noting the warning.      
>> 
>> Is it safe to execute on a live, active pool?
>> 
>> --m
>>  
> Yes.  No reboot necessary.
> 
> The Warning only applies to this circumstance:  if you''ve upgraded
from an older build, then upgrading the zpool /may/ mean that you will NOT be
able to reboot to the OLDER build and still read the now-upgraded zpool.
> 
> 
> So, say you''re currently on 111b (fresh 2009.06 build).   It has
zpool version X (I''m too lazy to look up the actual version numbers
now).  You now decide to live on the bleeding edge, and upgrade to build 133. 
That has zpool version X+N.   Without doing anything, all pool are still at
version X, and everything can be read by either BootEnvironment (BE).  However,
you want the neat features in zpool X+N.  You boot to the 133 BE, and run
''zpool upgrade'' on all pools.  You now get all those fancy
features, instantly.  Naturally, these new features don''t change any
data that is already on the disk (it doesn''t somehow magically dedup
previously written data).  HOWEVER, you are now in the situation where you
CAN''T boot to the 111b BE, as that version doesn''t understand
the new pool format.
> 
> Basically, it boils down to this:  upgrade your pools ONLY when you are
sure the new BE is stable and working for you, and you have no desire to revert
to the old pool.   I run a ''zpool upgrade'' right after I do a
''beadm destroy <oldBE>''
I''d also add that for disaster recovery purposes you should also have a
live CD handy which supports your new zpool version.

Cheers,

Chris

Erik Trimble <Erik.Trimble at Sun.COM> writes:

[...]
> The Warning only applies to this circumstance:  if you''ve upgraded
> from an older build, then upgrading the zpool /may/ mean that you will
> NOT be able to reboot to the OLDER build and still read the
> now-upgraded zpool.
Lots of good details snipped... thanks for the full explanation.