info needed-upgrade 8.1 to 10.0 with zfs root

Daniel Staal DStaal at
Wed May 28 20:14:50 UTC 2014

--As of May 28, 2014 12:35:58 PM -0500, Gene is alleged to have said:

> What's "stamp bootloaders"? Does that have to do with booting from a zfs
> root?
> My main concern is the root on ZFS. I want to make sure I can boot this
> puppy  when all is said and done!

--As for the rest, it is mine.

'Stamp bootloaders' is the part that makes sure you can boot when done.  ;)

There have been upgrades to the ZFS filesystem between 8 and 10.  You can 
run without upgrading the filesystem to the newer version, but you'll lose 
features.  (Among other things.)  Basically, the newer versions of the file 
system software can read the older disks, but you can't use newer disks 
with the older software.

So, it's not much of a problem - just load the newer OS, and it reads 
everything fine.  Upgrading the disks can be done on the fly.

With one exception: If you are using ZFS as root, the bootloader has to 
have the new version of ZFS to read new disks.  Since you can upgrade on 
the fly, it's quite possible to use a system for months with the newer 
filesystem on disk, and then find yourself unable to reboot because the 
bootloader can't read it.

So: Make sure you update the bootloader.  ;)

ZFS will remind you of this - and give instructions - when you update it on 
the disks, and you can update ahead of time using the same formula you used 
to put the bootloader on in the first place if you want.  Mark had you 
updating at each stage - it's not necessary in theory (you can do it last 
thing - everything will should fine with the older disk format), but it's 
probably a good idea.

Daniel T. Staal

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