[ale] replacing disk sda

[Michael H. Warfield]

On Wed, 2014-04-23 at 13:31 -0400, Paul Cartwright wrote:
> On 04/23/2014 01:15 PM, Michael H. Warfield wrote:
> > The partition table starts at +01BEh in the first sector.  Everything
> > before that is boot code and grub / grub2 installs part of itself in
> > there.
> >
> > http://en.wikipedia.org/wiki/Master_boot_record
> I started reading that and my eyes glazed over...
> 
>  so, sfdisk just backs up the partition table, not the bootloader code?

Correct.

> if your MBR got wiped out and you restored from an sfdisk file, would it
> boot ( assuming your OS partitions were still there)..

Possibly, but not the way to bet.  Most drives have a default MBR on
them that may or way not work and would most certainly NOT contain grub.
OTOH, if you restored the entire drive from sector 0 onward, you would
restore the grub code to the MBR.  But...  If you restore a logical
backup of /boot, it probably won't boot until you rerun grub[2]-install
from a rescue CD.

> I just backed up my sda using clonezilla, restored it to a new drive,
> and I got booted to my grub menu.

I would hope that clonezilla would do the same right thing.  Looks like
it did.

> are there other ways to backup the MBR that include the bootloader (
> grub?) info?

dd if=/dev/sda of=mbr bs=512 count=1

Restore works the other way with the proviso that, if you make any
changes to the location of the /boot partition or restore a logical
backup, you'll probably have to rerun grub[2]-install to reinstantiate
the new information.

Regards,
Mike
-- 
Michael H. Warfield (AI4NB) | (770) 978-7061 |  mhw at WittsEnd.com
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