Boot Disk

[R. G. Newbury]

On 12/27/2011 11:21 AM, Jeffrey Ross wrote:

>> >  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?

>> >  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.

> 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.

There is a way to determine things remotely, if you do some setup 
beforehand.
Your two hard drives are otherwise (I presume) exactly alike.
Set them up similarly, *except* that both use all but a megabyte or so 
(or one cylinder's worth of blocks). Make that little extra into a 
partition on ONE of the disks.

You can then remotely use 'cat /proc/partitions' to show the attached 
drives and partition  sizes (or use 'sfdisk -uC -l').

The extra partition will denote which drive is being used as 'sda' or 
'sdb'. This method is independent of the contents of the disk.

You may be able to re-size both of them in place although it might 
require another site visit. I have NO idea if gparted can be made to 
work remotely with vnc etc.

Geoff