From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) by finch.gentoo.org (Postfix) with ESMTP id 25611138D14 for ; Sun, 12 Jul 2015 16:32:56 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 5CBA41401B; Sun, 12 Jul 2015 16:32:44 +0000 (UTC) Received: from mail-wg0-f52.google.com (mail-wg0-f52.google.com [74.125.82.52]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 1A7A8E089F for ; Sun, 12 Jul 2015 16:32:42 +0000 (UTC) Received: by wgmn9 with SMTP id n9so26860935wgm.0 for ; Sun, 12 Jul 2015 09:32:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=20120113; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-type:content-transfer-encoding; bh=SEuF8W8eJY4zYmB2GTUD376X1hlBTTf8qXaI/U13tuI=; b=Q9dOeEklW+NVpgzAI0HpU7dYq9N0rvPvEKe4VmGrR3T2hLZcrSeRnz4Auwfq3qQXLP zRKK4XmLEh1jcL8crtGbrUQtvcENnhtPw5wZ4Y0RwVIdOaYtaGXHfe8QlZnfnshaaflE uRwFEzeV2blG/I69aFfCmRqKzJ31+yZiKKPEJpbVaKd1RO0h5MQ1NLjv4oZg7uZGZCiB U4qYzSoEplPj596/2qOvzPcVmvhpzR021EZ3tnuhjCwoFp/6UAxr1c1QTZfYtC5YdpZi LqQD4jEpYp571uVeExdFk5BfZr7yajgeW30aR0T8OfHsLkne9CESBQMwhvSYPAeDDZ7x Z7OA== X-Received: by 10.195.13.113 with SMTP id ex17mr61685386wjd.17.1436718761722; Sun, 12 Jul 2015 09:32:41 -0700 (PDT) Received: from [192.168.178.21] (p4FC11386.dip0.t-ipconnect.de. [79.193.19.134]) by smtp.googlemail.com with ESMTPSA id gt10sm9559498wib.20.2015.07.12.09.32.39 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 12 Jul 2015 09:32:40 -0700 (PDT) Subject: Re: [gentoo-user] Securely deletion of an HDD To: gentoo-user@lists.gentoo.org References: <20150712143525.07b6bdf5@thetick> From: Volker Armin Hemmann Message-ID: <55A296A7.5070301@googlemail.com> Date: Sun, 12 Jul 2015 18:32:39 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.0.1 Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 In-Reply-To: <20150712143525.07b6bdf5@thetick> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Archives-Salt: 75e6d260-e583-41ad-8be9-5f6a310284f4 X-Archives-Hash: 970006abd5e020bccbc4e83e44b2ba82 Am 12.07.2015 um 14:35 schrieb Marc Joliet: > Hi, > > I have to failed drives that I want to give away for recycling purposes, but > want to be sure to properly clear them first. They used be part of a btrfs > RAID10 array, but needed to be replaced (with "btrfs replace"). (In the > meantime I converted the array to RAID1 with only two drives.) > > My question is how precisely the disks should be cleared. From various sources > I know that overwriting them with random data a few times is enough to render > old versions of data unreadable. I'm guessing 3 times ought to be enough, but > maybe even that small amount is overly paranoid these days? > > As to the actual command, I would suspect something like "dd if=/dev/urandom > of=/dev/sdx bs=4096" should suffice, and according to > https://wiki.archlinux.org/index.php/Random_number_generation#.2Fdev.2Furandom, > /dev/urandom ought to be random enough for this task. Or are cat/cp that much > faster? > > Any thoughts? > > Greetings actually 1 time is enough. With zeros. Or ones. Does not matter at all.