[linux-lvm] lvm and 'poor mans raid' on heterogenous hard drives!

[Andreas Dilger]

On Feb 20, 2002  16:40 -0800, Rupa Schomaker wrote:
> Andreas Dilger <adilger at turbolabs.com> writes:
> > Swap is a bad move, since you can just add multiple swap spaces with the
> > same priority (if you so choose) and it will do the striping for you.
> > Likewise, you could put each of the above trees on their own drive and
> > you would probably get better overall performance than striping.
> 
> This suggestion has always bothered me.  Yes, if all you care about
> performance, setting up swap this way works fine.  However, for every
> drive you add you increase the likelyhood that you're system will fail
> due to a drive failure (what happens when one of the swap slices
> suddenly dissapears?).
> 
> The better (IMO) suggestion is to use MD to setup RAID-1 mirrors and
> then swapadd those.  That way, if one of your drives go south, you
> still have a workable swap.

Well that is true of ANY setup that uses RAID-0/stripe, or any unmirrored
disk for that matter.  I am by no means advocating the use of striped swap,
just saying that to stripe at the physical layer is no benefit over letting
the swap do its own striping.

Cheers, Andreas
--
Andreas Dilger
http://sourceforge.net/projects/ext2resize/
http://www-mddsp.enel.ucalgary.ca/People/adilger/