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Date:      Fri, 24 Sep 2004 18:18:10 +0100
From:      Chris Elsworth <chris@shagged.org>
To:        Paul Mather <paul@gromit.dlib.vt.edu>
Cc:        freebsd-geom@freebsd.org
Subject:   Re: WARNING: Expected rawoffset 0, found 63 ?
Message-ID:  <20040924171810.GA80912@shagged.org>
In-Reply-To: <1096044939.9306.54.camel@zappa.Chelsea-Ct.Org>
References:  <20040924160620.GA77997@shagged.org> <1096044939.9306.54.camel@zappa.Chelsea-Ct.Org>

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On Fri, Sep 24, 2004 at 12:55:40PM -0400, Paul Mather wrote:
> On Fri, 2004-09-24 at 12:06, Chris Elsworth wrote:
> 
> > I feel I'm missing something blatantly obvious here. Is that offset of
> > 63 something to do with metadata? Have I not left any space for
> > metadata that I should have done? I was hoping that I'd be able to end
> > up applying this gmirror command to an existing disk with live data on
> > it, and then attach a free disk to achieve a complete mirror from an
> > existing system?
> 
> Intuitively, I'd say it was more logical to create the mirror first on
> the slice and *then* label/partition and newfs that.  In other words,
> attach the free disk and create the mirror on that (copying across data
> from the existing system).  Then, when you have the mirror running, add
> the old drive to it for a two-disk mirror.

Well, I think that's basically what I'm doing? I'm practising on the
free disk first (good job, really).

Starting with a completely fresh disk with no partition table
or anything (dd if=/dev/zero of=/dev/da1 count=100 should ensure that?)
I'm using sysinstall to create a slice; the Fdisk option in
sysinstall, and all I'm doing there is using the entire disk and
making it bootable. I save that out, then quit sysinstall and what I'm
left with is:

app1# disklabel -r da1s1
# /dev/da1s1:
8 partitions:
#        size   offset    fstype   [fsize bsize bps/cpg]
  c: 71119692        0    unused        0     0         # "raw" part, don't edit


Is that what you'd start off with? So then by mirroring the slice, I'd do:
gmirror label -hv gms1 da1s1

And then I can start partitioning in /dev/mirror/gms1a etc, after using
disklabel to create it.

But the gmirror command is where the problems start; see pastes of
disklabel on the gms1 device in first post.


> In my case, I was doing a fresh install onto a two-disk system.  I did a
> regular minimal install onto disk 1.  Then, I created slices on disk 2
> (I wanted one slice for a geom_mirror, another slice for a
> geom_stripe).  Next, I used glabel to label the slice on disk 2 I'd be
> using for my mirror.  (I want to be able to have the disks move ATA ids
> and not worry about breaking the mirror.)  I then created a geom_mirror
> using gmirror using the labelled provider as the sole provider (and
> using "-h" to hard-code the providers into the metadata).  Now I had my
> mirror.
> 
> Then, it was a matter of bsdlabelling the mirror.

At this point, or indeed, even now, if you disklabel -r on your mirror
device, does it not give you warnings about partition c? If not,
that's where we start to differ :)

> Kudos to Pawel for such a useful GEOM class!

Definitely, I've always been a fan of Solstice Disk-Suite on Solaris
and this looks like being a very good FreeBSD competitor :)

-- 
Chris



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