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 CE46E138D11 for ; Mon, 13 Jul 2015 11:04:36 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 48FDA14041; Mon, 13 Jul 2015 11:04:28 +0000 (UTC) Received: from mout.gmx.net (mout.gmx.net [212.227.15.18]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 0A45814038 for ; Mon, 13 Jul 2015 11:04:22 +0000 (UTC) Received: from thetick ([93.181.44.4]) by mail.gmx.com (mrgmx001) with ESMTPSA (Nemesis) id 0MDhny-1ZCxtS1nEU-00HB24 for ; Mon, 13 Jul 2015 13:04:20 +0200 Date: Mon, 13 Jul 2015 13:04:18 +0200 From: Marc Joliet To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] Securely deletion of an HDD Message-ID: <20150713130418.659d03e0@thetick> In-Reply-To: <55A296A7.5070301@googlemail.com> References: <20150712143525.07b6bdf5@thetick> <55A296A7.5070301@googlemail.com> X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.28; x86_64-pc-linux-gnu) 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 Content-Type: multipart/signed; micalg=pgp-sha1; boundary="Sig_/PCXjV1JrTQRtqjy7pdDlcPx"; protocol="application/pgp-signature" X-Provags-ID: V03:K0:FJE4BMy6TWhlAdBMdJEt8iFAAsuzqsadoYyUooRlkCgfFDfN2PP 49pTsezC/dzLA0lRYgyWTM94B0Teg7njCLUgapKpQ13wtzL1n7lgDzIxneYS3M+JyAZnjX8 P42fr3JVgYyxAIdVW/Nlt7uXhstH6JknLmBfta+uzLLUenWOVxyd3joIptpsbHoxWjM9L4g mdGh/2/X5oQgumXGbjt/Q== X-UI-Out-Filterresults: notjunk:1;V01:K0:PE/CPLwkekY=:BP/ldp0go9yb6OUbvxYd96 MqCdsWjWG9uWwzHUTIwPsXfGQ+KzttMzSxEW1WrL3oTOl/Z/e0hjLcN2swgXPGkvFGyRzAfTv yS6+8fIaD2nsWSIXJhiFDCEN+fyVgJLqAhwa5kT8RUh+eZEy9LSnNLuG5g8lwzcnBXKEOCveU j+yUqFVEt57x9yAmkgKeuqqGb3gl6a7ogObkq7/+cr8G2cfKbieu9sdBnVMrXDDWIKrGMUyJp g2dLt9qmNqGKjVVZCRWI20UqUjCIh1N822OdqF/GTCgjha3yuFKswV3YU1TpV4NStqN/7rBbk 5jIgezS0+FjvlwP6mxVEa3TcUnmkAHLWYbxKFZKxVqI0OTLRB4XYu1+CwkATjGbESFq6brI1I rv2RDPc4b1B3vWm2lxQNh72sypfuFFAw/x9YUF+u3pV+HNq6cMa+wv/6X0KpxOmoih9Q8akPy qkCFRYNUDa5YWdoxWNwxTJex3huOX967bQi3jRfcVcB4PjSAA59DoNC67zlLFmOm33Do/BdO4 dBZ4piz3vlLWznrRMBoM3HD4j7s8WxLB7wXJ5aMTRjnTb6TjKTpteApFBZ53dLYwrmCbySHY3 UrtxcE2pv671azNhgxrw1QPoPd+vrSQuTqj96HOnsdfj2R+HdigZmdWDylgYsmkMLZqSw5lZt TV6mNvTEux35gFaRQXlRQsTOuYrFqCnCoHYCN2ISW/+iOFw== X-Archives-Salt: f9b172ee-a040-4e00-8490-f58d0584d07f X-Archives-Hash: f4add0603c3ad79e6399b71f0c412676 --Sig_/PCXjV1JrTQRtqjy7pdDlcPx Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Am Sun, 12 Jul 2015 18:32:39 +0200 schrieb Volker Armin Hemmann : > 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 b= trfs > > 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 enou= gh, but > > maybe even that small amount is overly paranoid these days? > > > > As to the actual command, I would suspect something like "dd if=3D/dev/= urandom > > of=3D/dev/sdx bs=3D4096" should suffice, and according to > > https://wiki.archlinux.org/index.php/Random_number_generation#.2Fdev.2F= urandom, > > /dev/urandom ought to be random enough for this task. Or are cat/cp th= at much > > faster? > > > > Any thoughts? > > > > Greetings >=20 > actually 1 time is enough. With zeros. Or ones. Does not matter at all. If you look at my initial response to Rich, I already concluded that "one t= ime is enough", although I'm going to stick with whatever random data shred(1) produces. --=20 Marc Joliet -- "People who think they know everything really annoy those of us who know we don't" - Bjarne Stroustrup --Sig_/PCXjV1JrTQRtqjy7pdDlcPx Content-Type: application/pgp-signature Content-Description: Digitale Signatur von OpenPGP -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBAgAGBQJVo5syAAoJEL/Q5oYsiHj0OxAP/27nmfmIYSYBK3LXm8o32oe1 PFCBr2my4KkKH0t0s3/ZEU7VRMpmqH7iZgBMss04wXvFOEucM68HPYZMR4VLGhta xEGrCRsuSfnlnNZLqAYSBKvkESV+acrBEFlSz9W3LLG+efuCoLRfB90/hKG5j8cy QOtdNPZ3jvosBk4kQFPLlksVAd5ND/jlY8BIek7ZtZCIiaARdIRy7P3vN8/oIE8H bj+RT5yoKtOG5wp6QiwZwvfj5Q+6X7MpTV9eMdi+KiyIlzFZBsnhfK9hmmseTVMU N46i/fQ8iqU9a0iUHQuA3Tda+5ZN+pdD1RqeLXFwDdm7OHSvxc5rf+E8DdnNY5ZB pKSEtoSP5iBAikqgsRcHJjg5RLE3dF407dSJ4b031afPVC+ATuf8eP7p2jkWaaqe DEfuXrXn0EN8BpU/zAkcvkFn3jTr4ixgLCxoWtIhHaoC3IpN5Int1kVZI26kFhgO F/budCZH+JGRi/U+qhBexYUb9iCPX3yCqQmvgPZTbJOq/aE/q6pI2cS3Lf5GRUgw vsAHT70qg8DrQ5WF/igv++IvjG8GZvKo8MsqmmFHsEJU85BGeEPxsgDZD16JPMwa X5wxxPbDc7YBaCccegkJB+o5Q8gYrseyZrP6mR9OerWNBr90xW8qi73yckJgBHHF 4xG2mRL/poz/xeA+pYgP =tbwZ -----END PGP SIGNATURE----- --Sig_/PCXjV1JrTQRtqjy7pdDlcPx--