[sclug] RAID 1 adventure

[lug at assursys.co.uk]

On Sun, 22 Jun 2003, Neil Haughton wrote:

> I have my Windows drive C: on /dev/hda1, but it expects to find drive D: 
> what was my /dev/hdc1 which is of course no longer there. (C: is OS and 
> apps, D: contains all the data files). How do I tell Win98 to look on 
> partition /dev/hda10 for its drive D:?

I don't think you can. Windows (9x and below) names the drives by iterating
through all partitions it recognises over all drives present:

To illustrate (if I remember the algorithm correctly):

/dev/hda1 FAT      C:
/dev/hda2 FAT      F:
/dev/hda3 non-FAT  H:
/dev/hda4 extended
/dev/hda5 non-FAT  J:

/dev/hdb1 FAT      D:

/dev/hdc1 FAT      E:
/dev/hdc2 non-FAT
/dev/hdc3 FAT      G:
/dev/hdc4 extended
/dev/hdc5 FAT      I:

That sucks doesn't it? Don't mount UNIX-style points seem like a much more
sensible idea?

> I'm stuck with Win98 fer the missus, for the time being anyway :-) and I 
> want to avoid reinstalling it (for the zillionth time) if I can do so.

What I did was use command line regedit to export the registry to a text
file, edit the text file using sed under Linux, then re-import the registry.
Obviously, some applications see needed to be fixed manually.

Note: I don't really recommend this approach unless you're completely happy
with it. I was prepared for a re-install if necessary anyway, so there was
nothing for me to lose...

> In case anyone is wondering, the main point of introducing RAID 1 to my 
> machine is to protect data in the event of a Windows reinstall (which 
> I'm probably stuck with, from time to time). It's the next step up from 
> having all data on a separate drive (as I have had until now). I assume 
> Win98 won't support software RAID, but the idea is that after Windows is 
> used, Linux will resync the mirror drive when it nexts starts up, as 
> long as the Windows partitions are mounted. I trust I have this right?

I haven't tried that usage, but I _suspect_ it won't work as the partition
type will be 0xfd rather than one of the FAT types. OTOH, I'm not sure
Windows will care as long as it finds something that looks like a FAT
filesystem inside... :-]

Also, I'm not sure of any way to specify to the RAID layer which drive is to
be the "canonical" copy. You might find that on the first boot it copies
the contents of your empty partition over the working one!

Best Regards,
Alex.
-- 
Alex Butcher      Brainbench MVP for Internet Security: www.brainbench.com
Bristol, UK                      Need reliable and secure network systems?
PGP/GnuPG ID:0x271fd950                         <http://www.assursys.com/>