Re: RAID-6 horizontal grow

[Piergiorgio Sartor <piergiorgio.sartor@nexgo.de>]

Hi again,

I made a quick test, but that does not seem to
work, at least with RAID-6.

What I did was to create 4 loop devices of 128MB
and then a RAID-6, metadata 1.1, on top of that.
The I stopped the array and the loop, I added
another 128MB (added as in "dd ... >> file"),
run "losetup" again and "mdadm -A ...".
Then "mdadm --grow --size=max ...", but the size
of the array did not change from 256MB (2x128MB).
The loop devices are 256MB (wc -c /dev/loop..).

So, either I'm missing something or this type of
grow does not seem to affect RAID-6.

Any ideas?

Thanks again,

bye,

pg

On Fri, Apr 10, 2009 at 10:58:33PM +0100, Robin Hill wrote:
> On Fri Apr 10, 2009 at 11:54:35PM +0200, Piergiorgio Sartor wrote:
> 
> > Hi all,
> > 
> > is it possible to grow a RAID-6, not by adding
> > more drives, but by extending the partions which
> > are composing the array?
> > 
> > In other words, let's say I've "n" partitions of
> > "x" GB forming a RAID-6 array. After some time I
> > increase the size of each partition to "y" GB, of
> > course y > x.
> > Is it then possible to use the complete space
> > growing the array?
> > How?
> > 
> Yes - "mdadm --grow --size=max /dev/mdX".  You'll also need to grow the
> filesystem afterwards of course.
> 
> Cheers,
>     Robin
> -- 
>      ___        
>     ( ' }     |       Robin Hill        <robin@robinhill.me.uk> |
>    / / )      | Little Jim says ....                            |
>   // !!       |      "He fallen in de water !!"                 |



-- 

piergiorgio