(original article)

Re: Converting RAID5 to RAID6 and other shape changing in md/raid

19 August 2009, 20:56 UTC

Yes it is possible with the new code. However it isn't quite released yet (Though you can pull it from my git tree). You will need mdadm-3.1 and linux-2.6.31.

If you just want to change the chunk size, the new mdadm will do that for you
mdadm --grow /dev/mdX --chunk-size=128

If you want to reduce the number of devices in an array you can. You will have to shrink the filesystem first, then shrink the array with
mdadm --grow --array-size

and then change the number of devices.