[geeks] Pure ZFS machine - possible?

[Mike Meredith]

On Thu, 9 Nov 2006 15:34:27 -0700 (MST), Dan Duncan wrote:
> On Thu, 9 Nov 2006, Bill Bradford wrote:
> > I would wait until zfs-boot is an official feature.  "they're
> > working on it".
> 
> I goofed with ZFS a bit to try it out.  I liked it and it was pretty
> easy to manage but I was initially told it offered scalable raid5
> like storage and as far as I can tell it doesn't.  If I create a
> raidZ container of say 5 disks and then later expand it by one, it
> just concatenates the filesystem across the 5-disk raidZ and the

It's probably a very difficult problem to enlarge a raid5 (or raidz)
vdev non-destructively. The only storage vendor I know of that offers
anything like that is NetApp and they use RAID4 to allow this. 

You can expand a zpool and maintain resilience, but it requires two
disks to add a mirrored vdev ... not exactly what you want. What's worse
is if you add a single disk to a zpool that is resilient, you end up
with a non-resilient pool which you can't fix! (unless I've missed
something new)

> actually merge an additional drive into a raidZ container or do I just
> need to leave it alone longer and it will do this?  I'd love to make

Leaving it alone won't do anything. It'll stay as a zpool with two vdevs
... one collection of disks as a raidz vdev and a single disk vdev.

Whilst zfs has a few problems, pretty much everything else does too ...
you really don't want to hear me rant about EMC's Clariion arrays :)

-- 
Mike Meredith (http://zonky.org/)
 This message represents the official view of the voices in my head