Removing one drive from a RAID 1 setup?

Adam Hough adam at
Thu Aug 27 00:10:04 UTC 2009

On Wed, Aug 26, 2009 at 5:55 PM, Philip Rhoades<phil at> wrote:
> People,
> Mick wrote:
>> --- On Tue, 8/25/09, Bruno Wolff III <br... at> wrote:
>>>  Philip Rhoades <p... at>
>>> wrote:
>>> >
>>> > If I remove this drive, is it straightforward to
>>> continue using the
>>> > remaining drive (sdd) with it's normal ext3 partition
>>> and the data still
>>> > intact?
>>> It might mess up grub. But otherwise it should work.
>> I kind of did this.
>> I installed F11 to a raid-1 two sata drives.
>> I could not get it to boot, it wanted a BIOS ID.
>> My BIOS (MSI K9A2) lets me boot from raid, but it does not show up in the
>> first
>> screen.
>> The one with IDE/SATA drives shown.
>> Anyway I went into the BIOS and deleted the raid array.
>> When I tried to install F11 the drives were NOT detected by anaconda.
>> It seems that there are "ghost" dm partitions on them.
>> Anaconda sees them and dies.
>> I was able to install F10 and Mint, as well as XPx64, but not F11 or
>> F12-alpha.
>> Apparently this is a known bug in anaconda.
>> So you may be able to fix up your drive and boot it, you most likely will
>> not
>> be able to install to it.
>> Mick M.
> Sorry, I should have made it clear sdc & sdd RAID 1 drives are mounted on
> /home, the MBR etc is on sda (/) - but all the extra info was
> interesting/useful anyway!
> Thanks,
> Phil.
> --
> Philip Rhoades

Is sda and sdb a mirror as well? or do you just care about  /home?

If sda and sdb and if /boot is a mirrorred across the two drives then
you need to in most cases hand edit grub so that it will boot from
both drives.

This is a very good right up on how to make a bootable mirrored pair
of drives:

Also though I have not done a lot of benchmarking, you might want to
consider moving to MD RAID10 instead of RAID1 as i am assuming that
your are using the linux software raid.  The MD RAID10 has the
advantage of striping reads across the 2 drives, while RAID1 does its
read in parallel.

More information about the users mailing list