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Date: Thu, 9 Jul 2009 15:05:30 +0200
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From: =?ISO-8859-1?Q?Marius_N=FCnnerich?= <marius@nuenneri.ch>
To: Ivan Voras <ivoras@freebsd.org>
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Cc: freebsd-geom@freebsd.org
Subject: Re: glabel and real disk IDs
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On Thu, Jul 9, 2009 at 13:52, Ivan Voras<ivoras@freebsd.org> wrote:
> Hi,
>
> I've been working with glabels for a time and just remembered that ATA (a=
d)
> drives do in fact export the drive ID, for example:
>
> # diskinfo -v ad4
> ad4
> =A0 =A0 =A0 =A0512 =A0 =A0 =A0 =A0 =A0 =A0 # sectorsize
> =A0 =A0 =A0 =A0320072933376 =A0 =A0# mediasize in bytes (298G)
> =A0 =A0 =A0 =A0625142448 =A0 =A0 =A0 # mediasize in sectors
> =A0 =A0 =A0 =A0620181 =A0 =A0 =A0 =A0 =A0# Cylinders according to firmwar=
e.
> =A0 =A0 =A0 =A016 =A0 =A0 =A0 =A0 =A0 =A0 =A0# Heads according to firmwar=
e.
> =A0 =A0 =A0 =A063 =A0 =A0 =A0 =A0 =A0 =A0 =A0# Sectors according to firmw=
are.
> =A0 =A0 =A0 =A0ad:9QF4H15Y =A0 =A0 # Disk ident.
>
> # diskinfo -v ad6
> ad6
> =A0 =A0 =A0 =A0512 =A0 =A0 =A0 =A0 =A0 =A0 # sectorsize
> =A0 =A0 =A0 =A0320072933376 =A0 =A0# mediasize in bytes (298G)
> =A0 =A0 =A0 =A0625142448 =A0 =A0 =A0 # mediasize in sectors
> =A0 =A0 =A0 =A0620181 =A0 =A0 =A0 =A0 =A0# Cylinders according to firmwar=
e.
> =A0 =A0 =A0 =A016 =A0 =A0 =A0 =A0 =A0 =A0 =A0# Heads according to firmwar=
e.
> =A0 =A0 =A0 =A063 =A0 =A0 =A0 =A0 =A0 =A0 =A0# Sectors according to firmw=
are.
> =A0 =A0 =A0 =A0ad:9QF4EP7A =A0 =A0 # Disk ident.
>
> # diskinfo -v ad8
> ad8
> =A0 =A0 =A0 =A0512 =A0 =A0 =A0 =A0 =A0 =A0 # sectorsize
> =A0 =A0 =A0 =A0320072933376 =A0 =A0# mediasize in bytes (298G)
> =A0 =A0 =A0 =A0625142448 =A0 =A0 =A0 # mediasize in sectors
> =A0 =A0 =A0 =A0620181 =A0 =A0 =A0 =A0 =A0# Cylinders according to firmwar=
e.
> =A0 =A0 =A0 =A016 =A0 =A0 =A0 =A0 =A0 =A0 =A0# Heads according to firmwar=
e.
> =A0 =A0 =A0 =A063 =A0 =A0 =A0 =A0 =A0 =A0 =A0# Sectors according to firmw=
are.
> =A0 =A0 =A0 =A0ad:9QF4H16L =A0 =A0 # Disk ident.
>
> I don't think it would be hard to add a label parser to gather this
> information and export it as a label.
>
> The purpose of this would be to have a unique disk ID without explicitly
> setting a label (e.g. as is commonly advised for ZFS and drive swapping).
>
> Any objections?

I like the idea. If one should use it in which situation is something diffe=
rent.