gvinum raid10 stale

[Rick C. Petty]

On Mon, Dec 22, 2008 at 05:20:36PM +0100, Dimitri Aivaliotis wrote:
> 
> So, am I reading you (and Ulf's previous mail) correctly in that the
> example given in the Handbook is not expandable?
> 
>    volume raid10
>       plex org striped 512k
>         sd length 102480k drive a
>         sd length 102480k drive b
>         sd length 102480k drive c
>         sd length 102480k drive d
>         sd length 102480k drive e
>       plex org striped 512k
>         sd length 102480k drive c
>         sd length 102480k drive d
>         sd length 102480k drive e
>         sd length 102480k drive a
>         sd length 102480k drive b
> 
> I thought that this was the "mirror of stripes" that you describe above.

This is a mirror of stripes, but I'm not really sure what you gain by
staggering across all the drives like that.  Are you doing this for some
performance gain?  If you're really using five disks, you may wish to
consider raid5.  Otherwise, this looks like a mirror of stripes across five
disks.  Much prettier than what you posted originally.

> > I add to my mirrors regularly, usually just to move volumes around.  I
> > think the confusion here is the number of subdisks per plex that you have
> > which is unnecessary.
> 
> Ignoring my current configuration for the moment because of the
> confusion caused by it, how would I expand the above example by adding
> 5 additional disks?

Are you trying to add mirrors or did you want to increase your volume size?
You could increase the volume size, but the underlying filesystem would
need to be resized.  I'm not sure if gvinum lets you increase the volume
size.  If you just want to add another striped mirror:

plex org striped 512k volume raid10
 sd length 102480k drive f
 sd length 102480k drive g
 sd length 102480k drive h
 sd length 102480k drive i
 sd length 102480k drive j

> Thanks for your patience with me here.  I'm trying to understand how
> this should work.

No problem.  I would still recommend getting rid of the stripes to reduce
your complexity and simplify future additions, but that's my personal
preference.

-- Rick C. Petty