From owner-freebsd-questions@FreeBSD.ORG  Sun Dec 21 15:34:14 2014
Return-Path: <owner-freebsd-questions@FreeBSD.ORG>
Delivered-To: freebsd-questions@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115])
 (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by hub.freebsd.org (Postfix) with ESMTPS id 7D643F65
 for <freebsd-questions@freebsd.org>; Sun, 21 Dec 2014 15:34:14 +0000 (UTC)
Received: from l4ms.rz.uni-kiel.de (l4ms.rz.uni-kiel.de [134.245.11.212])
 (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits))
 (Client did not present a certificate)
 by mx1.freebsd.org (Postfix) with ESMTPS id 32DAC21F7
 for <freebsd-questions@freebsd.org>; Sun, 21 Dec 2014 15:34:13 +0000 (UTC)
Received: from localhost ([127.0.0.1])
 by l4ms.rz.uni-kiel.de with esmtp (Exim 4.82)
 (envelope-from <hukriede@lily.geomar.de>) id 1Y2iDM-0001nC-Ju
 for freebsd-questions@freebsd.org; Sun, 21 Dec 2014 16:14:36 +0100
X-Virus-Scanned: by amavisd-new (Uni-Kiel/l4ms-sc)
Received: from frontend1.mail.uni-kiel.de ([134.245.12.48])
 by l4ms.rz.uni-kiel.de with esmtps (TLSv1:DHE-RSA-AES256-SHA:256)
 (Exim 4.82) (envelope-from <hukriede@lily.geomar.de>)
 id 1Y2iDM-0001n0-Fn
 for freebsd-questions@freebsd.org; Sun, 21 Dec 2014 16:14:36 +0100
Received: from lily.geomar.de ([134.245.222.89])
 by frontend1.mail.uni-kiel.de with esmtps (TLSv1:DHE-RSA-AES256-SHA:256)
 (Exim 4.84) (envelope-from <hukriede@lily.geomar.de>)
 id 1Y2iDL-0001r2-Rf
 for freebsd-questions@freebsd.org; Sun, 21 Dec 2014 16:14:36 +0100
Received: from lily.geomar.de (localhost [127.0.0.1])
 by lily.geomar.de (8.14.9/8.14.9) with ESMTP id sBLFEZs7056242
 for <freebsd-questions@freebsd.org>; Sun, 21 Dec 2014 16:14:35 +0100 (CET)
 (envelope-from hukriede@lily.geomar.de)
Received: (from hukriede@localhost)
 by lily.geomar.de (8.14.9/8.14.9/Submit) id sBLFEYGW056241;
 Sun, 21 Dec 2014 16:14:34 +0100 (CET) (envelope-from hukriede)
Date: Sun, 21 Dec 2014 16:14:34 +0100 (CET)
Message-Id: <201412211514.sBLFEYGW056241@lily.geomar.de>
From: Wolfgang Hukriede <whukriede@geomar.de>
To: freebsd-questions@freebsd.org
Subject: Re: errors from external USB disk
MIME-version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 8bit
X-BeenThere: freebsd-questions@freebsd.org
X-Mailman-Version: 2.1.18-1
Precedence: list
List-Id: User questions <freebsd-questions.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-questions>, 
 <mailto:freebsd-questions-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-questions/>
List-Post: <mailto:freebsd-questions@freebsd.org>
List-Help: <mailto:freebsd-questions-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
 <mailto:freebsd-questions-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sun, 21 Dec 2014 15:34:14 -0000

El día Fri Feb 28 03:29:04 UTC 2014, Polytropon freebsd at edvax.de escribió:

> Probably the disk has exceeded its natural life time. :-)

Not necessarily.

> You are correct. The firmware maps defective blocks as long as
> there are spare blocks available. When the problem starts "bubbling
> up" to the I/O subsystem of the OS, it's usually out of spare
> blocks, which means that there are more than enough defects.

Afaik, the disk doesn't remap the bad sectors unless you're writing
to them. Doing otherwise would make the error pass by unnoticed, not
a good idea at all.

So Matthias was spot-on writing zeroes to the sectors in question.

I saved at least one disk this way myself.

Greetings, whukriede