vinum or gvinum on FreeBSD 5.4

[Paul Mather]

> On Thu, 2005-04-21 at 10:39 +0200, Claus Guttesen wrote:
> > Hi.
> > 
> > I may implement (g)vinum to stripe two 2 TB raid 5 volumes into a
> > single 4 TB vinum-volume. The volumes reside on a atabeast doing the
> > raid 5. The server is a 5.4 RC2 doing nfs on i386.
> > 
> > According to some threads gvinum may not be completely stable (in 5.3,
> > http://unix.derkeiler.com/Mailing-Lists/FreeBSD/current/2004-11/0537.html)
> > when doing raid 5 but works fine when striping.
> > 
> > Should I go vinum or gvinum? Will newfs have problems with a 4 TB
> > volume? Are there any performance-degradation doing striping?

I forgot to mention, but you should consult
http://www.freebsd.org/projects/bigdisk/ to get an idea of the current
state of play and issues regarding large disk handling in FreeBSD.
According to the table of userland tools, it should be okay to newfs a
file system > 2 TB, but you might not be able to fsck or dump/restore
it. :-(  Also, I think that page holds for -CURRENT, and may not apply
to 5.x.

But, Pawel Jakub Dawidek has worked on large disk support, and so
there's a good chance that his geom_stripe feature is able to handle > 2
TB sizes.  You could test it via gstripe on large swap-backed md
providers.

I also dimly recall you may run into problems running out of RAM trying
to fsck very large filesystems.

Cheers,

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

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