Re: RAID-6 horizontal grow

["NeilBrown" <neilb@suse.de>]

On Sat, April 11, 2009 6:23 pm, Piergiorgio Sartor wrote:
> Hi again,
>
> I answer to myself.
>
> It seems that the array needs to be assembled
> with "--update devicesize", so that later the
> "--grow --size=max" could really work.

I love it when people find out answers by themselves - it shows the
documentation isn't completely worthless :-)

>
> It also seems that "--update" works only with
> "--assemble".
> Is there any way to update the device size "live",
> i.e. without stopping and re-assembling the array?
> (and without failing/removing/adding components?).

I think so, but mdadm cannot do it for you (yet).

If you
  for i in /sys/block/mdX/md/dev-*/size
  do echo 0 > $i
  done

it will have much the same effect as --assemble --update devicesize

Then you can
   --grow --size=max

NeilBrown