Re: making a disk/slice bootable

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/