From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from v6.tansi.org (mail.tansi.org [87.118.116.4]) by mail.server123.net (Postfix) with ESMTP for ; Mon, 8 Feb 2016 22:08:32 +0100 (CET) Received: from gatewagner.dyndns.org (77-57-36-72.dclient.hispeed.ch [77.57.36.72]) by v6.tansi.org (Postfix) with ESMTPA id E5C9C20DC1FB for ; Mon, 8 Feb 2016 22:08:31 +0100 (CET) Date: Mon, 8 Feb 2016 22:08:31 +0100 From: Arno Wagner Message-ID: <20160208210831.GA8366@tansi.org> References: <20160206025854.GA5986@tansi.org> <56B56605.4030907@whgl.uni-frankfurt.de> <20160206100140.GU13740@yeono.kjorling.se> <56B641C2.4070400@whgl.uni-frankfurt.de> <20160206190916.GA20801@yeono.kjorling.se> <56B646EA.1050100@whgl.uni-frankfurt.de> <20160207230502.GA29215@tansi.org> <56B7E07B.2000906@whgl.uni-frankfurt.de> <20160208164143.GB5543@tansi.org> <20160208203105.3CE48402ED@darkstar.media.mit.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160208203105.3CE48402ED@darkstar.media.mit.edu> Subject: Re: [dm-crypt] The future of disk encryption with LUKS2 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: dm-crypt@saout.de On Mon, Feb 08, 2016 at 21:31:05 CET, f-dm-c@media.mit.edu wrote: > > Date: Mon, 8 Feb 2016 17:41:43 +0100 > > From: Arno Wagner > > > The thing is that in a typical PC, power drops relatively > > slowly and disks work non-seeking for a lower voltage > > that the thresholds. Add to that that a single sector > > write takes less than 1ms (probably much less), and > > you get ample time to finish a write in progress. > > If the data has already made it all the way into the drive itself, > that may be valid, but it's very dangerous to make such assumptions > in general, and you can't necessarily know the timing of the power > failure vs when the data makes it to the disk, much less the platters. > > http://zork.net/~nick/mail/why-reiserfs-is-teh-sukc > > And new technologies may change this---not just SSDs, but modern > high-capacity drives that must rewrite many, many sectors to write > one. (Yes, I know this also argues that those headers should be > far away from each other. So be it. If such scattered headers > don't prevent resizing, I don't care. Except maybe for secure wipe.) My argument only relates to sectors getting corrupted by power failure, not other things. For that, the drive must become unable to write in mid-sector. Regards, Arno -- Arno Wagner, Dr. sc. techn., Dipl. Inform., Email: arno@wagner.name GnuPG: ID: CB5D9718 FP: 12D6 C03B 1B30 33BB 13CF B774 E35C 5FA1 CB5D 9718 ---- A good decision is based on knowledge and not on numbers. -- Plato If it's in the news, don't worry about it. The very definition of "news" is "something that hardly ever happens." -- Bruce Schneier