From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jurriaan Subject: Re: new superblock and raid10 support in mdadm Date: Tue, 14 Sep 2004 08:40:51 +0200 Sender: linux-raid-owner@vger.kernel.org Message-ID: <20040914064051.GA28661@middle.of.nowhere> References: <1095088590.3713.4.camel@rich> <16710.17573.491674.378912@cse.unsw.edu.au> Reply-To: Jurriaan Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <16710.17573.491674.378912@cse.unsw.edu.au> To: linux-raid@vger.kernel.org List-Id: linux-raid.ids From: Neil Brown Date: Tue, Sep 14, 2004 at 11:08:53AM +1000 > A new format is being supported because the old format has problems. > One is that it cannot work with devices larger than 2 Gigabytes (and I > have had a request from someone who wanted to include such a device in > an MD array). I presume you mean terabyte, but I'm not sure you don't mean petabyte or something else very large? > The raid10 module is in 2.4.9-rc2 and will be in 2.4.9 when it gets > released. 2.6.9 I presume? > /* > * RAID10 provides a combination of RAID0 and RAID1 functionality. > * The layout of data is defined by > * chunk_size > * raid_disks > * near_copies (stored in low byte of layout) > * far_copies (stored in second byte of layout) > * > * The data to be stored is divided into chunks using chunksize. > * Each device is divided into far_copies sections. > * In each section, chunks are laid out in a style similar to raid0, but > * near_copies copies of each chunk is stored (each on a different drive). > * The starting device for each section is offset near_copies from the starting > * device of the previous section. > * Thus there are (near_copies*far_copies) of each chunk, and each is on a different > * drive. > * near_copies and far_copies must be at least one, and there product is at most ----------------------------------------------------------their > * raid_disks. > */ Good luck, Jurriaan -- If you hear muffled screams, consider it a request for beam out. Tom Paris in Voyager Debian (Unstable) GNU/Linux 2.6.9-rc1-mm4 2x6209 bogomips load 0.14