[OFFTOPIC] Re: software raid1

[Tomáš Ebenlendr]

I marked this offtopic, as this has nothing to do with grub2 development...

On 22 Březen 2006, 1:43, Carl Karsten napsal(a):
> I have been messing around with software raid1 - mirroring 2 drives -
> including
> the boot sectors. The goal is to be able to remove either drive and still
> have a
> functioning system.
>
> I realize that this is "not supported" given that "Add support for
> software
> RAID" is on the http://grub.enbug.org/TodoList but I have heard it can be
> done
> with some trickery: install grub on both drives and rely on the fact that
> /dev/hda1 and /dev/hda2 and /dev/md0 are all "the same thing" as long as
> md0 is
> the only one that gets written to.


I think so. (You must instruct grub that your (hd0) is /dev/md0, and
then do everything like there was only one drive.)


> I did run into one problem:  if you have ide master and slave, and you
> pull the
> master, the slave dissapears and the box/bios won't see it so it won't
> boot from
> it.  so I am guessing I have to make each drive the master on a seperate
> ide bus
> so that pulling one won't take out the other.
>
> Before I spend too much time trying to make this work, anyone know of a
> HowTo
> that outlines this?
>
> CarlFK

As the RAID HOWTO says: if you have 2 IDE discs in raid on one IDE bus, it
is likely the fault of master drive causes data fault of slave. So you
should use 2 IDE buses anyway. (Otherwise you have same fault-tolerancy as
with one drive and no RAID.)
(here are hw issues: http://www.tldp.org/HOWTO/Software-RAID-HOWTO-4.html)

-- 
                                            Tomas 'Ebi' Ebenlendr
                                            http://get.to/ebik