Richard Freeman <rich@...> posted
463D15D0.1030105@..., excerpted below, on Sat, 05 May 2007
> Ok, I am trying to get my raid working. I have /dev/hda,b,c,d and
> /dev/sda,b,c. My boot partition is on /dev/sda1 and /dev/sdb1
> So, how do I set that up?
> Grub gives me:
> grub> find /boot/grub/stage1
> You can ignore hd0,0 - that is my old non-raid boot partition - it will
> get blown away once I'm migrated to the raid.
> I'm not sure if the drive numbers that grub sees will change when I boot
> off of sda or sdb. I did try to set things up following the various
> howtos and it didn't work, but they all tend to assume your boot drive
> is hd0.
> Any pointers? And don't ask why I have so many drives and am only now
> starting to set up a RAID... :) Suffice it to say my current lvm
> config makes me nervous...
Sounds like you /should/ be nervous. =8^(
OK, I'm tired and I'm not sure I'm answering the question you are asking
as I'm not sure I'm correctly parsing it, but let's see if this helps.
Think of it this way, when each drive is configured in BIOS to boot,
it'll probably see itself as hd0, with the BIOS switching around the
others accordingly to make it that way.
Rather than try to figure out which drive was which and get grub
installed correctly in them all (I have four in my RAID) from my running
system, I installed grub to a floppy, and booted that, so all the hard
drives appeared in their "natural" BIOS order. Then one by one, I
installed to them from the floppy, then when I was done, I tested by
pointing the BIOS at each one to boot from, and then doing the same
thing, but with the other drives removed, to be sure it could find grub
and grub could find /boot on the single remaining drive of the mirror set
with or without all the others in the mirror set there.
As noted above, with the BIOS pointed at a drive to boot, it may see
itself as hd0, regardless of where it's normally located. You can test
this, by configuring root (hd0,0) for each install, then point the BIOS
at it and see if it find /boot. If it does, you know that's what the
BIOS is doing, reassigning each drive as the first one. If it doesn't,
you know that it's not, and you probably need to use root (hd3,0) when
installing grub. Once grub is installed, however, you may be able to
boot it and figure out where it needs to point, if it's not pointed at
the right place.
Hope that helps, and didn't leave you even more confused. I know I did
it, but I took it a step at a time, and as I said, installed grub to a
floppy and booted it to figure out what was going on, then installed to
the hard drive from the floppy.
Duncan - List replies preferred. No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master." Richard Stallman
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