Re: making a disk/slice bootable

Thanks! That worked just fine but the mirrored/cloned disk has issues. And
with no way to get 11.x source, I think I have some decisions to make about
this system: upgrade and somehow move all the services across or just quit
pretending I understand any of this stuff.

Thanks again for the help…

On Thu, Sep 1, 2022 at 5:52 PM Dan Mahoney <freebsd@gushi.org> wrote:

> I haven't used recoverdisk.  If you're going to mirror, use one of the
> other things I mentioned.  gmirror is low-impact and easy enough to use and
> supported by the various boot loaders.
>
> If you're just cloning disk to similar disk with rsync, you should not
> need to do this more than once, unless maybe if you upgrade your system.
> Normal freebsd-update upgrades do not generally touch the boot blocks.  The
> best advice I can give is "test this BEFORE you need it".  Rip your primary
> drive out and see if you still boot.
>
> For a lightweight system, even zfs mirroring is okay, but it does use some
> ram for caching and the like, so I wouldn't try it with a tiny embedded box.
>
> -Dan
>
> On Sep 1, 2022, at 17:47, paul beard <paulbeard@gmail.com> wrote:
>
> yeah, I was pretty sure I was using the wrong tool…thanks for this.
>
> So a further Q…if I continue to use recoverdisk from ports to mirror my
> boot disk to a copy, is it best practice to do this on the mirror after the
> mirroring is completed? For all I know there is a far better way to do that
> but this is a FreeBSD 11 system (!) that has just been doing its thing for
> some years. So it worked (more or less) when it was set up. A backup you
> can't use isn't much use, as I have learned (again, I expect).
>
> On Thu, Sep 1, 2022 at 5:20 PM Dan Mahoney <freebsd@gushi.org> wrote:
> >
> > Fdisk is for old-school partitions (where disks had only 1-4 primary
> partitions, and then subdivided those partitions into "slices" (bsdlabel).
> >
> > I'm pretty sure the command you're looking for is:
> >
> > gpart bootcode -b /boot/pmbr -p /boot/gptboot -i 1 ada1
> >
> > In english, this says:
> >
> > * Stick the "protective master boot record" on the root of the disk
> (/boot/pmbr)
> > * Write a partition boot label from the file specified...
> > * to this indexed partition (-i 1)
> > * ...on ada1
> >
> > From there, you may need to tell the stage 0 loader where to find your
> next bootable partition on the next boot() prompt.
> >
> > -Dan
> >
> >
> > > On Sep 1, 2022, at 16:44, Dan Mahoney <freebsd@gushi.org> wrote:
> > >
> > >
> > >
> > >> On Sep 1, 2022, at 16:41, paul beard <paulbeard@gmail.com> wrote:
> > >>
> > >> I have been mirroring the virtual disk in a FreeBSD vm for a couple
> of years and the main disk got corrupted. The mirrored disk doesn't boot,
> says it can't find a kernel, so I think I missed out on an additional step,
> writing an MBR or boot sector, perhaps.
> > >>
> > >> The files are all there if I mount them from a VM with FreeBSD.I
> assume there is a way to make a mountable disk bootable.  fdisk and gpart
> are available but it's been a long time since I messed around with those.
> > >
> > > Let's start with the obvious: Can you post your disk layout?  Mirrored
> how?  Gmirror/ZFS/Hardware raid/etc?  MBR or Gpart?
> > >
> > > What commands have you tried thusfar?
> > >
> > > What does the boot so far look like (i.e. are you hitting the stage 0
> boot loader, and getting the loader prompt?)
> > >
> > > More info required, please, but this sounds very fixable.
> > >
> > > -Dan
> >
>
>
> --
> Paul Beard / www.paulbeard.org/
>
>
>

-- 
Paul Beard / www.paulbeard.org/