Boot disk?

[jeff at bubble.org]

> On Sun, Dec 25, 2011 at 2:37 PM, Jeffrey Ross <jeff at bubble.org> wrote:
>> Is there a way to identify which disk the BIOS is using to boot from (eg
>> disk 0 or 1) when I don't have physical access to the system to view the
>> BIOS settings?
>>
>> The situation is this, I have a machine at a remote location where the
>> system runs RAID-1 and both disks (0 and 1) can boot the system, I need
>> to
>> rewrite the boot sectors on the disks and I don't have easy access to
>> the
>> machine so I have to be careful as to which order I do them.
>
> If both disks have identical bootloaders, I'm not sure there's any way
> from a running system to check which one you booted from.  If you
> don't mind rebooting it, you could add a different arbitrary kernel
> argument to the GRUB configuration of each disk's bootloader, reboot
> the machine, then check /proc/cmdline to see which one shows up.
>
> That being said, why does the order matter?  So long as you do both
> correctly before rebooting the machine all should be well.
>

In this case it turns out it was booting off of sda (which is what I
suspected), I ended up taking a ride down to the datacenter and verifying
the BIOS.

The original question although no longer important remains, can you tell
which disk the initial load occurred from?  I did run dmidecode and found
nothing of value.

Thanks, Jeff