Re: resizing of raid5?

[Andreas Dilger <adilger@turbolinux.com>]

Neil Brown writes:
> On Wednesday August 1, hyperion@gnyrf.net wrote:
> > Just figured if anyone could give some information about resizing of
> > software raid5 systems (2.4.x kernels)? I've been looking all over for
> > information about if this is possible or not currently, and if not, how
> > this system of raid cluster blocks work in conjunction with ext2.
> 
> The only way to resize a raid5 array is to back up, rebuild, and
> re-load.  Any attempt to re-organise the data, or the linkage, to
> avoid this would be more trouble that it is worth.

Hmm, this surprises me.  I would have thought it possible to do
"resizing" at least by adding new stripes to the end of the current
RAID 5 volume, using N+1 new "disks" to make up a new stripe group.

Adding a new disk into the stripe set and re-striping the whole thing
is definitely a lot harder.

Cheers, Andreas
-- 
Andreas Dilger  \ "If a man ate a pound of pasta and a pound of antipasto,
                 \  would they cancel out, leaving him still hungry?"
http://www-mddsp.enel.ucalgary.ca/People/adilger/               -- Dogbert