Date: Fri, 29 Jun 2007 13:07:31 -0700 (PDT) From: Arne "Wörner" <arne_woerner@yahoo.com> To: Harry Newton <hn+freebsd@yewbarrow.net> Cc: freebsd-geom@freebsd.org Subject: Re: gmirror on a slice uncertainty Message-ID: <963281.43796.qm@web30315.mail.mud.yahoo.com> In-Reply-To: <87fy4a1rmn.fsf@vm.yewbarrow.net>
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--- Harry Newton <hn+freebsd@yewbarrow.net> wrote:
> >> - and this line in /var/log/messages:
> >> WARNING: Expected rawoffset 0, found 41929650
> >>
> > 41929650 == 41929587+63
> > This is the beginning of slice 2 (see fdisk)...
> > I would guess, that slice 2 ends on the last sector of the disk, so that
> > gmirror is disturbed (it doesnt know if ad4 or ad4s2 (which share both the
> > same last sector) is its underlying disk)...
>
> I haven't followed this. If I look at the disk with sysinstall:
>
> Disk name: ad4 FDISK Partition
> Editor
> DISK Geometry: 38913 cyls/255 heads/63 sectors = 625137345 sectors
> (305242MB)
>
> Offset Size(ST) End Name PType Desc Subtype
> Flags
>
> 0 63 62 - 12 unused 0
> 63 41929587 41929649 ad4s1 8 freebsd 165
> 41929650 583207695 625137344 ad4s2 8 freebsd 165
>
> 625137345 5103 625142447 - 12 unused 0
>
Ohoh... OK - so ad4 and ad4s2 do not share the last sector...
That makes my theory worthless...
> I see there's space at the end of the disk. The code that produces the
> message is in geom_bsd.c and is:
>
> if (rawoffset != 0 && (off_t)rawoffset != ms->mbroffset)
> printf("WARNING: Expected rawoffset %jd, found %jd\n",
> (intmax_t)ms->mbroffset/dl.d_secsize,
> (intmax_t)rawoffset/dl.d_secsize);
>
Hmm... Dont know what that might mean...
> But I'm now confused as to what the importance of this message is ?
>
I would guess, geom_bsd pulls it straight automatically...
You could test that by comparing the files tempX and tempY:
% dd if=/dev/ad4s2 iseek=0 of=/tmp/tempX count=128
% dd if=/dev/ad4 iseek=41929650 of=/tmp/tempX count=128
% cmp /tmp/temp[XY]
> > You could solve that
> > 1. by using hard coded disk names in gmirror
>
> Is this to prevent ad4 and ad4s2 being confused ? Doesn't gmirror know
> what the components that make up the provider are ?
>
Yup... But that seems to be no problem here...
So "hardcoded" would make no sense here...
What about my idea to not use any bsdlabel on mirror/home?
U can just delete it with:
% dd if=/dev/zero of=/dev/mirror/home count=16
-Arne
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