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Date: Sat, 8 Oct 2011 14:04:26 +0400
From: Lev Serebryakov <lev@FreeBSD.org>
Organization: FreeBSD
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Message-ID: <338510238.20111008140426@serebryakov.spb.ru>
To: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
In-Reply-To: <32040.1318061934@critter.freebsd.dk>
References: Your message of "Fri, 07 Oct 2011 17:41:59 CST."
	<alpine.BSF.2.00.1110071734140.4137@wonkity.com>
	<32040.1318061934@critter.freebsd.dk>
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Cc: Warren Block <wblock@wonkity.com>, freebsd-current@freebsd.org,
	Garrett Cooper <yanegomi@gmail.com>, Glen Barber <gjb@freebsd.org>,
	"Andrey V. Elsukov" <bu7cher@yandex.ru>, Benjamin Kaduk <kaduk@mit.edu>,
	Arnaud Lacombe <lacombar@gmail.com>
Subject: Re: aliasing (or renaming) kern.geom.debugflags
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Hello, Poul-Henning.
You wrote 8 =EE=EA=F2=FF=E1=F0=FF 2011 =E3., 12:18:54:

> gmirror and this procedure has several problems:
> 1. It steals the last sector on the disk.  If that sector contained data
>    you lost them, with no notice.  Most often it will not, particularly
>    on a freshly installed system, but it is still a bad thing.

> 2. The paritioning is not fixed up to record the stealing of this sector.
>    I wouldn't be surprised if this could cause confusion down the road.
  Yes, see discussion about GPT and MBR problems in thread, which is
named (and should be re-named already, really) "RFC: Project
geom-events"

> This is the kind of usage that makes me sad I ever added that option.
  Storing metadata of GEOM in last (or first) sector plays bad with
MBR and, especially, GPT :( And I cannot see good solution for this.

  It seems, that GPT will be incompatible with any pure-software
 mirror or mirror-like RAID.

--=20
// Black Lion AKA Lev Serebryakov <lev@FreeBSD.org>