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Date: Mon, 26 Jun 2006 15:50:46 +0300 (EEST)
From: Dmitry Pryanishnikov <dmitry@atlantis.dp.ua>
To: Pawel Jakub Dawidek <pjd@freebsd.org>
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Cc: Poul-Henning Kamp <phk@phk.freebsd.dk>,
	John-Mark Gurney <gurney_j@resnet.uoregon.edu>, freebsd-arch@freebsd.org
Subject: Re: Accessing disks via their serial numbers.
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Hello!

On Mon, 26 Jun 2006, Pawel Jakub Dawidek wrote:
>>>> When is it not acceptable ?
>>>
>>> When last sector is already occupied.
>>
>> And what is last sector occupied by ?
>
> This is simlar situation to the most common problem with gmirror(8).
> When people decide to put their file system onto a mirror, it will eat
> partition's last sector, which isn't always safe.
> When disk is already partitioned and file systems are there, you cannot
> just take the last sector.

  I'm repeating my recent post to -current, just for the record... Actually,
there IS the way to tell whether the last sector is in use on UFS, and
reserve it from futher use by FS. It's badsect(8). Just declare the last 
sector as bad, and then (if badsect has succeeded == sector isn't in FS's 
critical area) fsck will tell you whether this sector is free or is it used by 
another file. In the last case, fsck will tell you what file uses this sector 
(== multiple allocation in this file and in the just created BAD/xxx file) so 
you can just copy it's contents to another place and then remove it while 
keeping BAD/xxx.

Sincerely, Dmitry
-- 
Atlantis ISP, System Administrator
e-mail:  dmitry@atlantis.dp.ua
nic-hdl: LYNX-RIPE