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

Karl F. Larsen klarsen1 at gmail.com
Tue Feb 2 14:29:08 UTC 2010

Lawrence Tsang wrote:
> 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
> loss.
>      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.
> Regards
> Lawrence
> 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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	I took dmraid to Google and read the stuff on the Debian web 
page. As always they say if you use dmraid improperly, you can 
loose data. This means to me you had better rsync or copy all 
your data to a portable hard drive before you try to make both 
HD seperate.

73 Karl


	Karl F. Larsen, AKA K5DI
	Linux User
	#450462   http://counter.li.org.
         Key ID = 3951B48D

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