[dm-devel] Status of resizing/growing dm-multipath devices on the fly

[Pasi Kärkkäinen]

On Wed, Aug 06, 2008 at 03:48:12PM +0200, Domenico Viggiani wrote:
> * Pasi Kärkkäinen wrote:
> > 
> > Is it possible to resize (grow) dm-multipath devices on the 
> > fly nowadays?
> > 
> > I googled and found some discussions about the subject, but 
> > the conclusion seemed to be it's not possible.. that was a 
> > while ago, so I was wondering if this has been fixed/implemented..
> > 
> > Using LVM and adding another new LUN/PV is not an option 
> > always.. it's a lot easier to manage the whole thing if it's 
> > possible to resize/grow existing LUNs on the fly.
> 
> Nowadays all disk-arrays make online LUN extension a breeze but
> unfortunately it seems that dm-multipath is still not able to see new size
> without downtime:
>  http://www.redhat.com/archives/dm-devel/2007-August/msg00205.html
> Look also at this recent thread on RHEL5 mailing-list where you can find
> also a post from a Red Hat representative:
>  http://www.redhat.com/archives/rhelv5-list/2008-July/msg00267.html
> 
> Sure, you can just add a new LUN, pvcreate and vgextend but it is not a
> viable solution because it causes LUN proliferation.
> 
> Sincerely, I'm still subscribed to this mailing-list only to see if someone
> solve this SHAME!
> It's a feature that Linux really needs.
> 
> Hope someone pick this cry of pain!
> 

Thanks for the reply.

Does someone know what's the actual problem in this? meaning why it hasn't
been done yet.. 

-- Pasi