From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wes Felter Subject: Re: A simple, generic DM-API, for codecs/transcoders to use? Date: Mon, 22 Jun 2009 18:13:48 -0500 Message-ID: References: <49C0B79A.9010601@googlemail.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <49C0B79A.9010601@googlemail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: dm-devel@redhat.com List-Id: dm-devel.ids Navid Zamani wrote: > Hello DM mailing list. > > I a have a simple question: > Is there a way to use the device-mapper to hang an arbitrary program > in-between a real block device, and the virtual device created by the > device-mapper? http://static.danplanet.com/dm-userspace/ > In case you are interested in the reasons: Modern consumer HDDs do not > have any ECC, but they get less and less reliable. I don't think this is correct. All disks use ECC; cheap disks just don't use strong enough ECC. 4K sectors may fix this in the distant future. > So I decided to put my whole archive on a partititon with software-based > ECC. And because I could not find something that resembled this, I chose > to implement it myself. Honestly I would use RAID + Btrfs instead of software ECC. But if you're determined to go down this path, you may want to investigate LDPC instead of RS. Wes Felter - wesley@felter.org