From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pigeon.gentoo.org ([69.77.167.62] helo=lists.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.60) (envelope-from ) id 1L6O2Q-0000lr-Oq for garchives@archives.gentoo.org; Sat, 29 Nov 2008 11:31:02 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id E64BEE0330; Sat, 29 Nov 2008 11:30:59 +0000 (UTC) Received: from out5.smtp.messagingengine.com (out5.smtp.messagingengine.com [66.111.4.29]) by pigeon.gentoo.org (Postfix) with ESMTP id C627CE0330 for ; Sat, 29 Nov 2008 11:30:59 +0000 (UTC) Received: from compute1.internal (compute1.internal [10.202.2.41]) by out1.messagingengine.com (Postfix) with ESMTP id 2C9971821F2; Sat, 29 Nov 2008 06:30:59 -0500 (EST) Received: from heartbeat1.messagingengine.com ([10.202.2.160]) by compute1.internal (MEProxy); Sat, 29 Nov 2008 06:30:59 -0500 X-Sasl-enc: Y76ABb65iaTg6FRAn2bdP1rRkJMGjvCD+sqKeR9MamGI 1227958258 Received: from [192.168.2.2] (dslb-088-075-020-154.pools.arcor-ip.net [88.75.20.154]) by mail.messagingengine.com (Postfix) with ESMTPSA id 799FF2D4BF for ; Sat, 29 Nov 2008 06:30:58 -0500 (EST) Message-ID: <493127DB.9040009@f_philipp.fastmail.net> Date: Sat, 29 Nov 2008 12:30:35 +0100 From: Florian Philipp User-Agent: Thunderbird 2.0.0.18 (X11/20081124) 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 To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] Re: [OT] filesystems References: <1227479490.26615.47.camel@rattus> <200811252007.55035.volker.armin.hemmann@tu-clausthal.de> <38af3d670811251124v7d447918v82b7ec11baafd1a9@mail.gmail.com> <200811252102.52130.volker.armin.hemmann@tu-clausthal.de> <38af3d670811251219n4c531baft7aa37951271b7f00@mail.gmail.com> <492c6aef.uN1RRcHNp8dUe+Nc%Joerg.Schilling@fokus.fraunhofer.de> <38af3d670811251600m784f43c3i944a4ac56b001c49@mail.gmail.com> <492D5CAF.3010504@f_philipp.fastmail.net> <38af3d670811282201u6b802b57nbf41d187b6fb30f1@mail.gmail.com> In-Reply-To: <38af3d670811282201u6b802b57nbf41d187b6fb30f1@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Archives-Salt: 8d8a3dec-a231-49cc-a927-491eda93b23b X-Archives-Hash: 4fefd7329f9109f9351cc7e2e18609fd Jorge Peixoto de Morais Neto schrieb: > On Wed, Nov 26, 2008 at 12:26 PM, Florian Philipp > wrote: >>> As for my photos, I can back all the collection to a single DVD (and >>> to a second one, since I keep hearing that DVD-Rs are unreliable), and >>> since I don't take new photos every week, this solution is fine. >>> >> A second DVD-R won't solve the problem because optical disks degrade over >> time and the second one will degrade just as fast as the first. What you >> need to do is to check the disks periodically (once a year is a good time >> frame). > I know DVD-Rs degrade, but it is unlikely they would fail at the same > time, so copying twice does significantly alleviate the problem > (AFAIK) I'm not so sure in this regard. If we were talking about HDDs you were right: it is very unlikely for two of them to fail at the same time due to mechanical defects. But we are talking about optical media. They fail because of chemical reactions. That's why two disks, stored equally, bought at the same time from the same trader, produced by the same company, should degrade equally fast and therefore fail at about the same time. And since you want to check them less than once a year, "at about the same time" means within the same year. > Once a year isn't overkill? Isn't once every two years fine? > I'm not sure. I myself wouldn't trust normal CD/DVD-Rs for more than three years and CD/DVD-RWs for more than one year (cheap RWs degrade much faster than Rs). Additionally, having such long intervals between checks makes it easier to forget them completely. Can you remember whether you checked your disks last year or the year before? I know I couldn't. > Sure. I am doing that since some time now. Unfortunately I didn't do > so for some old backups. But data DVD-Rs have a considerable amount of > correction code, and if the copy from DVD to hard disk proceeds > without a single error message, there is a quite good chance that the > files are good, right? I would think so.