[PLUG] boot from USB, run on RAID?

Robert Citek robert.citek at gmail.com
Tue Jun 17 18:14:17 UTC 2008


On Tue, Jun 17, 2008 at 9:51 AM, Kurt Sussman <plug at merlot.com> wrote:
> Robert Citek (robert.citek at gmail.com) typed this ...
>> In the photos you'll see that I use Grub to choose from among eight
>> (8) OS installs on a single USB drive, including Debian, Ubuntu, and
>> CentOS.  I created that drive using instructions almost identical to
>> the one's I wrote in the previous post.
>
> You have most certainly 'touched' the Windows drive. All of those boot
> off the same physical device, but from different partitions.

Sort of.  Yes, all the Linux installs boot off different partitions on
the same drive, the external USB drive.  But the Windows installation
is on a completely separate drive, the internal SATA drive.  Remove
the USB drive and there is only Windows.  Remove the internal drive
and plug in the USB drive, and there are only the different Linux
installs.

I can also boot Windows from grub on the USB drive by dropping to a
grub command line and typing this:

map (hd0) (hd1)
map (hd1) (hd0)
rootnoverify (hd1,0)
makeactive
chainloader +1
boot

Once Windows starts booting, I can unplug the USB drive.

> I can't do that because drivers need to be loaded to recognize the
> drives as a RAID1 pair before any information there is usable. So I have
> to boot a kernel off another device (the USB stick in question), load
> the drivers, then mount the RAID device and make it the new root.
>
> Does this make more sense?

Makes perfect sense.  And is doable.  The instructions in my first
post get you about 90% of the way there.  After that add the kernel to
the USB stick and an appropriate stanza in the menu.lst file.

Regards,
- Robert



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