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Subject: Re: How to safely remove rest of GTP?
To: Slawa Olhovchenkov <slw@zxy.spb.ru>
References: <20161230124407.GN37118@zxy.spb.ru>
 <d79b8568-72e8-415e-4923-14e3c730267e@FreeBSD.org>
 <20161230164652.GO37118@zxy.spb.ru>
Cc: freebsd-hackers@freebsd.org
From: "Andrey V. Elsukov" <ae@FreeBSD.org>
Message-ID: <22d5dece-f14b-3bef-b3dd-8bb6226e0d28@FreeBSD.org>
Date: Fri, 30 Dec 2016 20:08:55 +0300
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On 30.12.2016 19:46, Slawa Olhovchenkov wrote:
> On Fri, Dec 30, 2016 at 07:28:19PM +0300, Andrey V. Elsukov wrote:
>
>> On 30.12.2016 15:44, Slawa Olhovchenkov wrote:
>>> How to safely remove rest of GPT?
>>> Disk have actual data (part of ZFS), I am don't need to destroy this
>>> data.
>>>
>>> GEOM: da6: the primary GPT table is corrupt or invalid.
>>> GEOM: da6: using the secondary instead -- recovery strongly advised.
>>> GEOM: da22: the primary GPT table is corrupt or invalid.
>>> GEOM: da22: using the secondary instead -- recovery strongly advised.
>>> GEOM: da6: the primary GPT table is corrupt or invalid.
>>> GEOM: da6: using the secondary instead -- recovery strongly advised.
>>> GEOM: da22: the primary GPT table is corrupt or invalid.
>>> GEOM: da22: using the secondary instead -- recovery strongly advised.
>>
>> You may try attached patch, I did only basic tests, so first try
>> somewhere :)
>
> What purpose of this patch?

In case when you have not valid primary header, `gpart destroy` will not 
touch first two sectors. In you case you can wipe only last sector, like 
Ian suggested, but use 'gpart destroy -F da6' instead of dd.

-- 
WBR, Andrey V. Elsukov