Vinum migration 4.x-5.4

[Paul Mather]

On Fri, 19 Aug 2005 11:01:55 -0500, Robin Smith
<rasmith at aristotle.tamu.edu> wrote:

> There seems to be a consensus in the references I've found that vinum
> is completely broken on 5.4 and that gvinum/geom_vinum is not ready
> for production use.  As it seems to me, this means that anyone using
> 4.11 (say) and vinum will have to abandon vinum (i.e. quit doing
> software
> RAID) in order to upgrade to 5.4.  That can be both laborious and slow
> (e.g. if you have /usr on, say, a four-drive vinum volume in 4.11,
> you're
> going to have to replace those drives with something else in order to
> go
> to 5.4.  Is that false, and is there a relatively simple way to get 
> geom_vinum in 5.4 to read a vinum configuration produced under 4.11
> and
> start the vinum volume as it is?

I am using geom_vinum on RELENG_5 without problems.  However, I use only
mirrored and concat plexes, and most of the problems I've heard people
experiencing involve RAID 5 plexes.

Geom_vinum uses the same on-disk metadata format as Vinum, so it will
read a configuration produced under 4.x---in fact, this was one of its
design goals.  BTW, Vinum is not the only software RAID option under
5.x: you can use geom_concat (gconcat) or geom_stripe (gstripe) for RAID
0; geom_mirror (gmirror) for RAID 1; and geom_raid3 (graid3) for RAID 3.
I successfully replaced my all-mirrored geom_vinum setup in-place on one
system with a geom_mirror setup.

Finally, if you are migrating from 4.x to 5.x, you might consider a
binary installation with restore rather than a source upgrade.  That
way, you can newfs your filesystems as UFS2 and get support for, e.g.,
snapshots, background fsck, etc.

Cheers,

Paul.
-- 
e-mail: paul at gromit.dlib.vt.edu

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