From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pigeon.gentoo.org ([208.92.234.80] helo=lists.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.60) (envelope-from ) id 1OLJ9n-0005dA-KQ for garchives@archives.gentoo.org; Sun, 06 Jun 2010 16:57:07 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id B325DE0D87; Sun, 6 Jun 2010 16:56:13 +0000 (UTC) Received: from mail-wy0-f181.google.com (mail-wy0-f181.google.com [74.125.82.181]) by pigeon.gentoo.org (Postfix) with ESMTP id 110A1E0D87 for ; Sun, 6 Jun 2010 16:56:12 +0000 (UTC) Received: by wyb35 with SMTP id 35so1905868wyb.40 for ; Sun, 06 Jun 2010 09:56:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:from:reply-to:to:subject:date :user-agent:references:in-reply-to:mime-version:content-type :content-transfer-encoding:message-id; bh=twa6Gg0Jpj+5e6prvKlGzK4ZtnQUzwo/GcGaIN8ZSeI=; b=srXi48TemDqwuZG1dTPvOmRk4DpyUCjtD0puMvbfm+gYO1RD8T6arDIc4qWDCvwiZn jOU/8fTiUCk/ntlxMiqZjpoTKE0luuTOv2Y08tZ3Y7o8Q0p+lYSAyX+XM1xruzAxQwm/ 4ESWwAPQeZtly5SqiHL/AUo0EsqARjtSYlmng= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=from:reply-to:to:subject:date:user-agent:references:in-reply-to :mime-version:content-type:content-transfer-encoding:message-id; b=m7GadiY/L9BXXihBieBwqkolmAnQY8bsHTm2YMyRHq5fgXwjdqaZV+FWpXbOeEVGno AUwYd5ldQgMN5au05GQ/joD1UVph1dpCjqLJzWwdL/MydoJAEUbh4bq5IQKT7cTdsn+a +6QLJ8/ma+zaRiBimez8iS3BKO5AxVfKmaopc= Received: by 10.227.134.84 with SMTP id i20mr13292329wbt.52.1275843372305; Sun, 06 Jun 2010 09:56:12 -0700 (PDT) Received: from (230.3.169.217.in-addr.arpa [217.169.3.230]) by mx.google.com with ESMTPS id u36sm30076238wbv.12.2010.06.06.09.56.11 (version=TLSv1/SSLv3 cipher=RC4-MD5); Sun, 06 Jun 2010 09:56:11 -0700 (PDT) From: Mick To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] Re: Fast checksumming of whole partitions Date: Sun, 6 Jun 2010 17:55:59 +0100 User-Agent: KMail/1.12.4 (Linux/2.6.33-gentoo-r2; KDE/4.3.5; x86_64; ; ) References: <20100605063956.GA5125@solfire> <4C0AE15D.8020408@gmail.com> <4C0B764D.5030008@alyf.net> In-Reply-To: <4C0B764D.5030008@alyf.net> 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; boundary="nextPart51047683.1AKvOFFsV1"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit Message-Id: <201006061756.12438.michaelkintzios@gmail.com> X-Archives-Salt: 21642bc2-cd19-4b3e-8f3d-c43f67060802 X-Archives-Hash: 6503c7c666edc8c6a624ad823f2a5f34 --nextPart51047683.1AKvOFFsV1 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable On Sunday 06 June 2010 11:19:57 Andrea Conti wrote: > > 1. boot up knoppix > > 2. create a partition: mkdir /work > > 3. mount /work to the root partition: mount /dev/sdc /work > > 4. cd /work/usr/bin > > 5. run dcfldd: ./dcfldd >=20 > This is fine, provided that >=20 > 1- if the root partition is [part of] what you're copying, you *must* > mount it read-only (mount -o ro /dev/sdc /work) >=20 > 2- the dcfldd executable is linked statically. If it uses dynamic > linking, your "live" system -- knoppix in this case -- must have exactly > the same library versions (especially glibc) as the gentoo system. >=20 > >> Or is there a way to do such copies from a one disk to another while > >> one disk is booted??? >=20 > The point is not with being "booted" (i.e., part of the running system) > or not: you *cannot* reliably perform a sector-by-sector copy of any > write-mounted partition without special support either at the FS or > block device level (i.e. snapshots). >=20 > > Sure, but the running disk/sector would have temporary files that would > > not consistently hash when you did the hash check. >=20 > That is only a minor part of the problem. The real issue is that if > *anything* writes to the source partition while you are halfway through > copy, you risk ending up with inconsistencies in the filesystem > metadata. Doing a fsck on the copy will probably fix that, but you risk > losing or corrupting data. >=20 > And no, hashing as described in the previous post will *not* catch any > differences in this case, as the "source" hash is computed from what is > read during the copy (which, barring hardware problems, is what gets > written on the target disk) and not from the whole contents of the > source partition after the copy (or at any single point in time). >=20 > > If you do this, try it in linux without bringing up X. >=20 > That's definitely not enough: at the very least, boot up in single-user > mode and remount all your partitions read-only (mount -o remount,ro). > This will break things on a running system (e.g anything that writes to > /var and /tmp will throw errors or stop working), but it will allow you > to produce consistent partition images. It may be worth trying 'apt-get install dcfldd' after you su to root with=20 Knoppix. As long as Knoppix does not need a lorry load of dependencies you= =20 may be able to quickly install the .deb binary you need and move on with th= e=20 task in hand. =2D-=20 Regards, Mick --nextPart51047683.1AKvOFFsV1 Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.15 (GNU/Linux) iEYEABECAAYFAkwL0ywACgkQVTDTR3kpaLYmUwCgkvNkM+cKZ+B0OfyLrdN6FKCd eJEAnibIlHEHPp7HiiO3MI6HfYcQNwZf =xyZj -----END PGP SIGNATURE----- --nextPart51047683.1AKvOFFsV1--