undo geom mirror

[Joe Auty]

Hi Craig (sending this to the list too, for the general interest of  
whomever):

I tried this out on a test machine:

1) rolled back fstab to original (non-mirror version)
2) commented out automatic load of mirror in /boot/loader.conf
3) rebooted

This worked fine, however, going back to the mirrored version of  
fstab would even allow me to boot the machine until I deactivated the  
mirrored drive, and reattached it (which forced it to rebuild).

Not too difficult to do though. Now, I just need to know whether it  
is wise to ensure that no writing or changes to the disk are  
occurring when the drives are syncing for the first time. Any ideas?



On May 17, 2006, at 4:11 PM, Craig Ryhorchuk wrote:

> Good question, but I'd think there would be a chance of things getting
> messed up if the kernel thought you had a mirror and you were  
> trying to
> use the two drives independently.  Stuff like whatever you write to /
> ending up in the middle of your /usr partition on drive 2 as well.
> Or it might just not boot or maybe it'd work.  I'm not willing to try
> it just because I don't want to have to rebuild everything on the one
> server I have it set up on.
>
> -----Original Message-----
> From: Joe Auty [mailto:joe at netmusician.org]
> Sent: May 17, 2006 3:58 PM
> To: Craig Ryhorchuk
> Subject: Re: undo geom mirror
>
> Thanks for your response!
>
> So, basically, all I have to do is just undo fstab and loader.conf,
> and that will essentially get me back up and running? What would
> happen if I didn't remove the mirror?
>
> On May 17, 2006, at 3:40 PM, Craig Ryhorchuk wrote:
>
>> I'm sending this off-list because apparently even though spammers
>> have free posting access to the list, I don't.
>>
>> Just to be safe, I'd recommend removing your primary bootdisk from  
>> the
>> mirror, changing your /etc/fstab back to the original values as
>> well as /boot/loader.conf.
>>
>> At this point you should be safely able to simply boot from the
>> original
>> boot disk and remove the second drive from the GM and delete the  
>> whole
>> mirror.
>>
>> Make sure you have the boot CD available just in case.  If you
>> forget/mess up one step like I did when setting one up it's easy to
>> fix.
>>
>>  - Craig
>>
>> -----Original Message-----
>> From: owner-freebsd-questions at freebsd.org
>> [mailto:owner-freebsd-questions at freebsd.org] On Behalf Of Joe Auty
>> Sent: May 17, 2006 7:47 AM
>> To: FreeBSD Questions
>> Subject: undo geom mirror
>>
>> Hello,
>>
>> What is the best way to "undo" a geom-based mirror, just out of
>> curiosity, and return the configuration to allowing independent
>> control over the two disks?
>>
>> something like this?
>>
>> gmirror clear mirror/gm0
>> gmirror remove ad1
>> gmirror remove ad2
>>
>> - unload geom, remove from boot/loader.conf
>> - revise /etc/fstab
>>
>>
>> Please help me fill in the gaps here, I've never successfully done
>> this.... Or, is this procedure inadvisable?
>>
>>
>>
>>
>>
>>
>> -----------
>> Joe Auty
>> NetMusician: web publishing software for musicians
>> http://www.netmusician.org
>> joe at netmusician.org
>>
>>
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>