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Date: Tue, 26 Oct 2010 11:41:39 -0700
From: Malahal Naineni <malahal@us.ibm.com>
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Subject: Re: [linux-lvm] Determine boot disk device name...
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To: linux-lvm@redhat.com

Alexander Skwar [alexanders.mailinglists+nospam@gmail.com] wrote:
>    Hi!
>    2010/10/25 Malahal Naineni <[1]malahal@us.ibm.com>
> 
>      Alexander Skwar [[2]alexanders.mailinglists+nospam@gmail.com] wrote:
>      >    I also wanted to suggest this, but…
>      >
>      >    benutzer@horst:~$ cat /proc/cmdline
>      >    root=/dev/xvda1 ro
> 
>      I got confused with boot and root! Thanks for correction. Usually boot
>      disk is mounted at /boot. Your boot disk could be same as root disk (in
>      this case there would not be anything mounted at /boot but just a
>      directory).
> 
>    Well, but even the location of the /boot directory/partition doesn't
>    necessarily tell, from where someone booted - suppose, you've got
>    a boot disk /dev/sda. On /dev/sda, there's grub. Grub's setup so,
>    that it boots a system/kernel, which is on /dev/sdb. The system
>    is "self contained" on /dev/sdb.
> 
>    In such a case, the system would've been booted from /dev/sda,
>    but there's no way to tell that, once the "/dev/sdb system" has
>    been started - or is there?

Once loader's job is done, it is not needed and I don't think there is a
way to find out your boot disk in all __situations__ as I said before.
In fact, you can use a USB disk as your boot disk and remove it after
boot.

Thanks, Malahal.