Skip site navigation (1)Skip section navigation (2)
Date:      Wed, 21 Jan 2009 13:13:31 -0200
From:      Patrick Tracanelli <eksffa@freebsdbrasil.com.br>
To:        Jerry McAllister <jerrymc@msu.edu>
Cc:        stable@freebsd.org, Eduardo Meyer <dudu.meyer@gmail.com>, questions@freebsd.org
Subject:   Re: switching bsdlabel's label
Message-ID:  <49773B9B.4060402@freebsdbrasil.com.br>
In-Reply-To: <20090121150046.GA61468@gizmo.acns.msu.edu>
References:  <d3ea75b30901200724o4bc9b515y71733fcb2f5808f9@mail.gmail.com>	<20090120161355.GA28525@hugo10.ka.punkt.de>	<d3ea75b30901200936n15ae0b03m4c48ba55f3728d44@mail.gmail.com>	<20090120184216.GA57318@gizmo.acns.msu.edu>	<d3ea75b30901210445l70d48631r496d9f45db667be0@mail.gmail.com> <20090121150046.GA61468@gizmo.acns.msu.edu>

Next in thread | Previous in thread | Raw E-Mail | Index | Archive | Help
Jerry McAllister escreveu:
> On Wed, Jan 21, 2009 at 10:45:28AM -0200, Eduardo Meyer wrote:
> 
>> On Tue, Jan 20, 2009 at 4:42 PM, Jerry McAllister <jerrymc@msu.edu> wrote:
>>> On Tue, Jan 20, 2009 at 03:36:34PM -0200, Eduardo Meyer wrote:
>>>
>>>> On Tue, Jan 20, 2009 at 2:13 PM, Patrick M. Hausen <hausen@punkt.de> wrote:
>>>>> Hello,
>>>>>
>>>>> On Tue, Jan 20, 2009 at 01:24:27PM -0200, Eduardo Meyer wrote:
>>>>>> I have a certain disk where da0s1a and da0s1d are inverted. By some
>>>>>> reason someone labelled root as 'd' and home as 'a'.
>>>>>>
>>>>>> Can I just
>>>>>>
>>>>>> bsdlabel -n da0s1 > savedabel.txt
>>>>>>
>>>>>> Edit savedlabel.txt, switch and restore? (bsdlabel -R da0s1 savedlabel)
>>>>> Why not simply use bsdlabel -e da0s1?
>>>> Because I didnt know about that? ;-)
>>>>
>>>> Thank you for the hint.
>>>>
>>>> However I still have the same doubt. Since basically its the same
>>>> task, Is it safe do relabel this way?
>>> Hmmm.  Is there stuff written on the disk.  Is root stuff really written
>>> on da0s1d and /home stuff really written on da0s1a?   Does the system boot
>>> from it OK?
>>>
>>> Or is it just that the mounts are switched.
>>> The mount points are not written in to the label.   That comes after
>>> booting.   If it boots, I wonder if it really is switched on the
>>> partitions or if it is just that the partitions are mounted backwards
>>> (probably due to editing /etc/fstab incorrectly).
>>>
>>> ////jerry
>> Hello Patrick, thanks again. Yes, label is switched. Yes there really
>> are stuff on the partitions. No, I dont boot from da0s1d. It is a disk
>> for migration. But the one who partitioned was fooled by Sysinstall
>> which creates the first label on extra disks as 'd' and the last from
>> the allowed 7 as 'a'. Therefore this server is still booting on the
>> original disk (ad6s1a) and everything else is mounted in the new one
>> (da0s1), everything but root.
> 
> What sysinstall does is assume that the 'a' partition will be
> used for a root mount and the 'b' partition will be used for swap.
> Sinc 'c' is reserved, it starts with 'd'.   Then, if you later 
> add an 'a' it will end up being later (higher offset) than the 'd'.
> 
> I suppose it might confuse a person, but otherwise it is no problem
> and probably would be best to just leave it that way.   You really
> only need to use the mount point anyway most of the time.  So, if
> the mount point addresses the partition you want to with that name,
> then you should have no problem.
> 
> You could switch it around using bsdlabel, but I don't think the 
> risk would be worth the negligible gain.   But, do as you wish.
> 
> ////jerry     
> 
> 
>>>
>>>
>>>
>>>>> Kind regards,
>>>>> Patrick
>>>>> --
>>>>> punkt.de GmbH * Kaiserallee 13a * 76133 Karlsruhe
>>>>> Tel. 0721 9109 0 * Fax 0721 9109 100
>>>>> info@punkt.de       http://www.punkt.de
>>>>> Gf: Jürgen Egeling      AG Mannheim 108285

Hello,

Yes, you can do this change anytime you want, since (1) da0s1* are 
unmounted and (2) disk is clean. Therefore I suggest you are in single 
user mode. If you feel unsure, backup the current label scheme with

disklabel da0s1 -n > da0s1.disklabel.bk

You can restore anytime with the Rescue Disk.

Go ahead, no problem.

Sometimes you will really have problem booting from a disk if root is 
not on label 'a'. I believe it can be workarounded, but your will is 
safe, go ahead and switch the labels.

You can always remember the person who did this from sysinstall that 
sysinstall will label as 'a' if the mount point is root (/).

Therefore if someone wants to use sysinstall for labelling in 
production, and wont mount on / since / has the current root, one can 
always fool sysinstall, (C)reating the partition, using / as mpoint and 
mater redefining the (M)ount point to somewhere else, say, to /mnt.

I always relabel this way, never had a problem. TinyBSD sometimes 
relabels this way too, for some PC Engines Wrap boards. Go ahead.

-- 
Patrick Tracanelli

Tel.: (31) 3516-0800
316601@sip.freebsdbrasil.com.br
http://www.freebsdbrasil.com.br
"Long live Hanin Elias, Kim Deal!"




Want to link to this message? Use this URL: <http://docs.FreeBSD.org/cgi/mid.cgi?49773B9B.4060402>