From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.saout.de ([127.0.0.1]) by localhost (mail.saout.de [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id zkwgIrXgp4at for ; Wed, 16 Jan 2013 22:29:34 +0100 (CET) Received: from strike.wu.ac.at (strike.wu-wien.ac.at [137.208.89.120]) by mail.saout.de (Postfix) with ESMTP for ; Wed, 16 Jan 2013 22:29:34 +0100 (CET) Message-ID: <50F71BBB.2030603@strike.wu.ac.at> Date: Wed, 16 Jan 2013 22:29:31 +0100 From: Alexander 'Leo' Bergolth MIME-Version: 1.0 References: <50F6F2BE.9080203@strike.wu.ac.at> <50F7063B.9090607@strike.wu.ac.at> <20130116201455.GB9508@tansi.org> <50F712D8.801@strike.wu.ac.at> <20130116210840.GA10215@tansi.org> In-Reply-To: <20130116210840.GA10215@tansi.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [dm-crypt] migrate luks key-slots to another luks container List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Arno Wagner Cc: dm-crypt@saout.de Am 16.01.2013 22:08, schrieb Arno Wagner: > On Wed, Jan 16, 2013 at 09:51:36PM +0100, Alexander 'Leo' Bergolth wrote: >> Am 16.01.2013 21:14, schrieb Arno Wagner: >>> Any reason why you want to change the cipher? After all, you can >>> not enlarge the key and keep the keyslots. >>> >>> As to size, just enlarge the partition. Offset, I don't know, >>> but if you do not need to keep any data, just changing the >>> repective fiels in the header should do it. But is there really >>> any reason to change the offset? >> >> The motivation behind this is because I'd like to migrate the data >> to another system using a different raid layout. >> To ensure correct data alignment with the new stripe size, I need to >> change the payload-offset using --align-payload. > > Ah, that makes sense. However, do you actually need this > alignment? If yor filesystem has, say, 4kB blocks and your > stripe-size is a multiple of that, it will be aligned anyways. Unfortunately this isn't easy to achieve if you are using raid5 or 6. I am moving to a raid6 with 5 disks using 64k chunksize. 64k chunks multiplied by the number of data bearing disks (3) results in a stripe width of 192k (=384 blocks). Thus I guess I should use --align-payload=384. The current setting is different and even the default of 1MiB isn't a multiple of that value. Anyway, is the migration of keyslots possible in my case? Thanks, --leo -- e-mail ::: Leo.Bergolth (at) wu.ac.at fax ::: +43-1-31336-906050 location ::: IT-Services | Vienna University of Economics | Austria