CentOS - Apr 2012 - Installing CentOS 6.2 *TO* a USB drive, not installing from USB.

I'm trying to setup a very small system intended for doing
monitoring/logging. It's done on an Intel Atoms in a small box and the
idea was to simply run it off a pair of USB flash drives in software
RAID 1.

Now the problem is that while the 6.2 DVD installer could go through
the entire install process, grub will load then just stop at the
prompt. The system will work if I use a SATA hard disk so motherboard
compatibility is not an issue.

Attempting the various methods to re-install grub (via rescue mode) or
using the grub prompt to setup the disk does not work either. grub
just does not seem to be able to find the USB drives. e.g. commands
like root (hd0,0) just says device not found. This is despite grub
having just loaded from it and despite that grub-install in rescue
mode does not report any error.

Same problem even if I just go with one USB drive in a plain vanilla ext3 setup.

It seems that some sites are saying that EL variants just don't seem
to be adaptable to installing and running off USB drives. Is this
really the case and that I should be looking at using another
distribution or am I just missing some crucial steps in the process?

On 04/04/2012 11:46 AM, Emmanuel Noobadmin wrote:
> just does not seem to be able to find the USB drives. e.g. commands
> like root (hd0,0) just says device not found. This is despite grub
hd0,0 represents the bios device id, are you sure thats what your bios
thinks the usb disk is at ?

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On Wednesday, April 04, 2012 12:38:03 PM Emmanuel Noobadmin
wrote:
> I also did try manually doing (hd0,1), (hd1,0) but none of it seemed
> to be a "findable" device. For what it's worth, the installer
did see
> them as sda and sdb. 
The grub order and names and the linux kernel/udev order and names should not be
assumed to have any correlation of any kind, since they are discovered
differently.

If you can boot a USB live media on this box, you could bring up a grub shell
and see how grub sees the disks from that (at a root prompt, type 'grub'
and you'll be greeted with the grub shell, and then you can do detection or
whatever from that).  This also works in the rescue environment given by the
install media; you do want to do a 'chroot /mnt/sysimage' in that shell
before entering the grub shell, though.

It is completely BIOS dependent as to how the devices show up to grub.