[lug] re: adding a device to existing RAID 0

[Brian Stiff]

>What I'd like to do is add a third device to increase
the capacity. 
>According to the man page and numerous examples I've
found, you can do this with:
>
>mdadm --add /dev/md0 /dev/sdd
>
>the catch is that all the examples I've seen were for
recovering a RAID-5
>(removing a failed device then adding one). Does
anyone know if this will work
>without destroying the existing data on a RAID-0? 

Unless I'm completely mistaken, you'd have to somehow
convert your existing RAID 0 to RAID 5.  RAID 0 only
allows mirroring two devices.  To add storage to the
array, you'd have change the array to "stripe" across
the drives, and I'm not aware of a method to
accomplish this with an existing array.  Your best
option would probably be to get another drive big
enough for all of the data on the RAID0 and copy your
data to the second spare drive.  You would then break
the RAID0, add your existing first spare drive to the
array, and set the array as a RAID5.  This will be a
time-consuming pain in the butt, so hopefully someone
else on the list knows more than I and can point you
in the correct direction.  I went through this
recently, but now I'm the happy owner of a .5 TB
RAID5.  :-)  Good luck!

-B


	
		
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