Fwd: Moving ZFS root popol to a virtual server was: ZFS: Suspended Pool due to allegedly uncorrectable I/O error

On Sun, Aug 25, 2024 at 2:30 AM Ronald Klop <ronald-lists@klop.ws> wrote:

>
> *Van:* Pamela Ballantyne <boyvalue@gmail.com>
> *Datum:* zondag, 25 augustus 2024 05:03
> *Aan:* freebsd-fs@freebsd.org
> *Onderwerp:* Moving ZFS root popol to a virtual server was: ZFS:
> Suspended Pool due to allegedly uncorrectable I/O error
>
> This is certainly possible but small details can result in a non-bootable
> pool on the target.
>
>
> Can you provide some information on how you moved the root pool to the
> virtual server?
> Did you dd the whole disk to a file? Or did you zfs send | zfs receive a
> snapshot? Or ... ?
> What boot-loader was used on the old server and what on the new one? Is
> the partitioning the same on both?
> I remember the old server had mirrored disks, how did you setup the
> virtual server?
>
>
Thank you, Ronald.  I still need to get the new server, I have a meeting
with the engineers at the hosting company tomorrow.
I will see what they have to offer.

To prepare for a migration, I've tried setting up a 13.4 server on
VirtualBox and then creating a second one as a target.
I've successfully done a ZFS send/recv and duplicated the original
installation on the target server.

But something quite strange did happen. I created the original with a
single two-disk mirror, but just made a single disk
pool on the target. Once the OS was successfully transferred, I configured
another virtual disk, identical to the pool disk
and tried to attach it. ZFS rejected it with "cannot attach ada0p3 to
ada1p3: can only attach to mirrors and top-level disks"

I looked around and found a suggestion to change vfs.zfs.min_auto_ashift
from 12 to 9, which I did (without understanding why), allowing me to add
the mirror successfully.

But this is strange because the original installation was created directly
from the FreeBSD install files, which should have set it to 12? It
certainly was for the creation of everything on the second system.

Hopefully, I will be able to duplicate this experience with the new host,
munis the shift setting!

Thank you *so* *much*
Pammy