[PVE-User] grub-install error: unknown filesystem, won't boot anymore

[arjenvanweelden at gmail.com]

On Mon, 2019-03-18 at 10:35 +0100, Wolfgang Link wrote:
> Hi Arjen,
> 
> thanks for this information.
> 
> We update the wiki with your information.
> 
You're welcome. Thank you for responding and changing the Wiki. An
unbootable rpool can be a rather unexpected surprise.

I now have an rpool (that does not boot because of large dnodesize),
and a tpool (dnodesize=legacy, taken from a fresh installation).

Grub boots the kernel from tpool/ROOT/pve-1, which then mounts rpool.
This works but it would be nice to remove this work-around.

Would rsyncing from rpool/ROOT/pve-1 to tpool/ROOT/pve-1 and renaming
tpool to rpool be sufficient to get a booting and working rpool?

Best regards, Arjen

> Best Regards,
> 
> Wolfgang Link
> 
> > arjenvanweelden at gmail.com hat am 8. März 2019 um 21:21 geschrieben:
> > 
> > 
> > Apologies for replying to myself.
> > 
> > On Fri, 2019-03-08 at 11:12 +0100, arjenvanweelden at gmail.com wrote:
> > > Dear readers,
> > > 
> > > My up-to-date (no-subscription) Proxmox installation at home
> > > stopped
> > > booting properly. GRUB complains at boot about:
> > >   error: no such device: <hex string>.
> > >   error: unknown filesystem.
> > > 
> > > I got my system booting again using a new installation of Proxmox
> > > on
> > > a USB-stick, because Rescue Boot option of the installation ISO
> > > did
> > > not
> > > work for me. Fortunately, my 4-way mirror rpool is just fine (as
> > > are
> > > the other ZFS pools), but grub-install, grub-probe, and insmod
> > > normal
> > > at GRUB prompt keep returning "error: unknown filesystem".
> > > 
> > > Last thing I did to my rpool was 'zfs set dnodesize=auto rpool'
> > > as
> > > suggested on the ZFS Tips and Tricks official Wiki-page.
> > > Reverting to dnodesize=legacy did not fix the GRUB boot issue.
> > > 
> > 
> > zpool get all rpool shows:
> >   rpool  feature at large_dnode  active  local
> > 
> > I guess this make me run into a GRUB bug?
> >   https://savannah.gnu.org/bugs/?func=detailitem&item_id=48885
> > If so, suggesting 'dnodesize=auto' on the Proxmox Wiki might not be
> > the
> > best idea until the bootloader used by Proxmox supports it?
> > 
> > > Currently, my system is booting partially from the USB-stick and
> > > partially from my original rpool, which works but is not ideal.
> > > Does someone recognize this problem? Does anyone know a fix?
> > > 
> > 
> > Is there a way to disable/undo large_dnode?
> > 
> > kind regards, Arjen
> > 
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>