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 A132B1381F3 for ; Mon, 6 May 2013 18:38:35 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id A206CE08A1; Mon, 6 May 2013 18:38:22 +0000 (UTC) Received: from outpost1.zedat.fu-berlin.de (outpost1.zedat.fu-berlin.de [130.133.4.66]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 73A65E0898 for ; Mon, 6 May 2013 18:38:21 +0000 (UTC) Received: from inpost2.zedat.fu-berlin.de ([130.133.4.69]) by outpost1.zedat.fu-berlin.de (Exim 4.80.1) for gentoo-user@lists.gentoo.org with esmtp (envelope-from ) id <1UZQIm-0027gf-3d>; Mon, 06 May 2013 20:38:20 +0200 Received: from dslb-188-102-020-107.pools.arcor-ip.net ([188.102.20.107] helo=BIFROST.fritz.box) by inpost2.zedat.fu-berlin.de (Exim 4.80.1) for gentoo-user@lists.gentoo.org with esmtpsa (envelope-from ) id <1UZQIl-002k3I-U8>; Mon, 06 May 2013 20:38:20 +0200 Date: Mon, 6 May 2013 20:36:33 +0200 From: Hinnerk van Bruinehsen To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] Recover on SSD Message-ID: <20130506183632.GA11132@BIFROST.fritz.box> References: <20130505161640.GB30557@BIFROST.fritz.box> <20130506110021.GB2702@BIFROST.zedat.fu-berlin.de> <5187E99C.2030105@googlemail.com> 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; protocol="application/pgp-signature"; boundary="fdj2RfSjLxBAspz7" Content-Disposition: inline In-Reply-To: <5187E99C.2030105@googlemail.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Originating-IP: 188.102.20.107 X-Archives-Salt: 965f167b-a86e-43e2-9ece-808a8aa07edb X-Archives-Hash: 873c768580397fc605a1291e14de8986 --fdj2RfSjLxBAspz7 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, May 06, 2013 at 07:34:20PM +0200, Volker Armin Hemmann wrote: > emm - no. Wear leveling does not need any spare blocks. A lot of drives > do have spare blocks, but those are never the same size of the original > size (at least not on drives you can buy for a sensible amount of > money). More like 120+8 or 160+16 or 256+16. >=20 > The spare blocks are used like on a hdd: some block goes bad, another > one is mapped in. >=20 > Since the sdd firmware does not know if something was deleted or not* - > it does know shit about filesystems**, you can of course dd an image, if > you want to. Just like on a hdd. >=20 > *there are drives that do garbage collection without TRIM for fat and or > ntfs.. so they seem to know a bit about filesystems. >=20 > ** and this is why TRIM exists in the first place. To tell the drive: > yes, this data is gone. You don't need to care about it anymore. The actual numbers were made up to make the point (maybe I should have stated that in my OP). According to [1] they are normally between 7% - 37%. Linux supports TRIM since Kernel 2.6.28. It's supported for several filesystems (Ext4, Btrfs, FAT, GFS2 and XFS) but must be enabled via the discard mount option. I don't have definitive information for Windows but it seems to be supported by at least Windows 7 (as far as I can tell without any user interaction). Since the "deletion" happened under Windows I made a guess that it is not totally unreasonable that dd may not work (if the deleted data would have been "TRIMed"). [1] http://www.lsi.com/downloads/Public/Flash%20Storage%20Processors/LSI_PR= S_FMS2012_TE21_Smith.pdf --fdj2RfSjLxBAspz7 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) iQEcBAEBAgAGBQJRh/gwAAoJEJwwOFaNFkYcwa8IAJBH8rvDe8UcNCiVGaN6mefb Ji3mHVRVB30c/et86iUK+HVvSGoWri1NaZ4w7KQq8t5zjcwRcoXetnHA7euqcIib 1F/qRcokKb6LP2Tb5Xx0InsFkJkOW0YP1SRKeZiB2v4Ki7xj8d/cO5Ps0a72zNLu RjIUJbX9CYXxBABRhSMWLh8BU9Ybm8uUOd0amEa81QerKHQm1zfXfAZbrrDFap1m FCq7JKoj09nGVXQkPQ0kP/d1iklvkWvd3eJR8bCEnWgQnTKZsPg3USTNRKAoxN+c 7MVnXlv+yHIRS44bkbb3+8Qper6TapZ8s/6zPWbskW/BXOTAXjXyCuWxBTJq1Cs= =Bt5/ -----END PGP SIGNATURE----- --fdj2RfSjLxBAspz7--