Ubuntu 9.10 Desktop CD booted system could not mount internal harddisks attached to a RAID motherboard

Lawrence Tsang tkwinfo at gmail.com
Tue Feb 2 14:11:49 UTC 2010

Hi Tom and All,

     Thanks for the update.

     I expect the command "dmraid -an" in a root terminal would do the job
of de-activating the detected BIOS RAID set while keeping the metadata of
the BIOS RAID set. (At this mean time I don't want to remove the settings
(metadata) in the RAID BIOS, I may remove it later.)

     I am now in the testing period of Ubuntu 9.10. I do not prepare to
install Ubuntu 9.10 Desktop into my internal harddisk yet. I just want to
boot my system using the 9.10 CD and use the booted system to access all my
internal and removable disks. So I expect to perform some commands in the
booted system in order to de-activate the remaining RAID set and recover
access to my internal disk partitions.

      Thanks for Tom pointing out that RAID set de-activation may not
destroy data in the relating harddisks. I want to make sure that the
concrete command "dmraid -an" would not cause me trouble by making any data

     Does anyone have the experience of using such dmraid command that is
doing what I expect it to do here ?

     Moreover, suppose "dmraid -an" does the right job, how could I recover
access to sda1, sda2 and sdb1 ? I could not afford a reboot as I am using a
CD to boot which always returns my system to the same initial conditions.

     Glad to have your helpful suggestion.


On Tue, Feb 2, 2010 at 8:00 AM, Tom H <tomh0665 at gmail.com> wrote:

> > Thanks for the suggestion.
> > root at ubuntu:/dev/mapper# dmraid -r
> > /dev/sdb: isw, "isw_dfbbifjhde", GROUP, ok, 488397166 sectors, data@ 0
> > /dev/sda: isw, "isw_dfbbifjhde", GROUP, ok, 488397166 sectors, data@ 0
> >  My motherboard has an Intel Software Raid that I had once set my two
> > 250GB internal harddisks into RAID 1. I have (about 1 year ago) then
> decided
> > not to use RAID 1 and set (in the normal BIOS) the two internal disks
> back
> > into independent IDE disks. However, I don't know whether the RAID 1
> setting
> > remains in the RAID BIOS or not.
> > It seems that Ubuntu 9.10 Desktop may have recognized my two internal
> > IDE disks as a RAID set.
> > How should I remove the RAID set and release my 2 internal disks as
> > independent IDEs. The commands used must NOT destroy my data in the two
> > internal disks.
> You're welcome.
> The raid set is probably being activated because of the remaining raid
> metadata from your experiment.
> The activation of the raid set is not deleting your ntfs data on sda1,
> sda2, and sdb1, is it? So the deactivation will not do so either.
> mdadm allows you to unmount a raid device, disable it, and delete its
> raid metadata without destroying the "real" data so dmraid must too.
> If/once you follow the three steps above, purge dmraid from the CD
> before launching the installer in order to disallow it from
> re-detecting the raid set.
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