zfs discuss - Feb 2008 - zfs send / receive between different opensolaris versions?

Hello everybody,

I''m thinking of building out a second machine as a backup for our mail
spool where I push out regular filesystem snapshots, something like a  
warm/hot spare situation.

Our mail spool is currently running snv_67 and the new machine would  
probably be running whatever the latest opensolaris version is (snv_77  
or later).

My first question is whether or not zfs send / receive is portable  
between differing releases of opensolaris.  My second question (kind  
of off topic for this list) is that I was wondering the difficulty  
involved in upgrading snv_67 to a later version of opensolaris given  
that we''re running a zfs root boot configuration
--
Michael Hale                                           			<mhale at
transcomus.com
 >
Manager of Engineering Support 				Enterprise Engineering Group
Transcom Enhanced Services					http://www.transcomus.com

On Wed, 2008-02-06 at 13:42 -0600, Michael Hale wrote:
> Hello everybody,
> 
> I''m thinking of building out a second machine as a backup for our
mail
> spool where I push out regular filesystem snapshots, something like a  
> warm/hot spare situation.
> 
> Our mail spool is currently running snv_67 and the new machine would  
> probably be running whatever the latest opensolaris version is (snv_77  
> or later).
> 
> My first question is whether or not zfs send / receive is portable  
> between differing releases of opensolaris.  My second question (kind  
> of off topic for this list) is that I was wondering the difficulty  
> involved in upgrading snv_67 to a later version of opensolaris given  
> that we''re running a zfs root boot configuration

For your first question, zfs(1) says:

     zfs upgrade [-r] [-V version] [-a | filesystem]

         Upgrades file systems to a  new  on-disk  version.  Once
         this  is done, the file systems will no longer be acces-
         sible on systems running older versions of the software.
         "zfs send" streams generated from new snapshots of these
         file systems can not  be  accessed  on  systems  running
         older versions of the software.

The format of the stream is dependent on just the zfs filesystem version
at the time of the snapshot, so as they are backwards compatible, a
system with newer zfs bits can always receive an older snapshot. The
current filesystem version is 3 (not to be confused with zpool which is
at 10), so it''s unlikely to have changed recently.


The officially supported method for upgrading a zfs boot system is to
BFU (which upgrades ON but breaks package support). However, you should
be able to do an in-place upgrade with the zfs_ttinstall wrapper for
ttinstall (the Solaris text installer). This means booting from CD/DVD
(or netbooting) and then running the script:
http://opensolaris.org/jive/thread.jspa?threadID=46588&tstart=255
You will have to edit it to fit your zfs layout.
> --
> Michael Hale                                           			<mhale at
transcomus.com
>  >
> Manager of Engineering Support 				Enterprise Engineering Group
> Transcom Enhanced Services					http://www.transcomus.com
> 
> 
> 
-Albert