Help with RAID-1 sofware mirror?

[Rashkae]

David Vincent wrote:
> Can anyone point out some good reading on the subject of software raid 
> under Ubuntu?  I have a mirror setup which I want to break and I'm not 
> sure how to manage it easily without copying partitions all over the place.
> 
> Thanks
> 
> -d
> 
See: http://tldp.org/HOWTO/Software-RAID-HOWTO.html

and man mdadm


In a nutshell, you want to use mdadm to mark one of your raid partitions 
as "faulty", after which you can remove it from the raid set.  Note that 
  Linux will always consider the partition a Raid partition, even if 
there is only one disc left (called a degraded RAID partition).  On the 
plus side, you can always rebuild the mirror by adding an empty 
partition of equal or greater size to the array with mdadm.