From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6272EC43461 for ; Wed, 12 May 2021 18:55:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2FFD0613EE for ; Wed, 12 May 2021 18:55:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237683AbhELSsD (ORCPT ); Wed, 12 May 2021 14:48:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45086 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347761AbhELR3j (ORCPT ); Wed, 12 May 2021 13:29:39 -0400 Received: from u17383850.onlinehome-server.com (u17383850.onlinehome-server.com [IPv6:2607:f1c0:83f:ac00::a6:f62a]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 6ED5EC061760 for ; Wed, 12 May 2021 10:28:31 -0700 (PDT) Received: by u17383850.onlinehome-server.com (Postfix, from userid 5001) id D13C376B; Wed, 12 May 2021 13:22:42 -0400 (EDT) Date: Wed, 12 May 2021 13:22:42 -0400 From: David T-G To: list Linux RAID Subject: Re: raid10 redundancy Message-ID: <20210512172242.GX1415@justpickone.org> References: <8626adeb-696c-7778-2d5e-0718ed6aefdb@redhat.com> <6db10ef4-e087-3940-4870-e5d9717b853f@thelounge.net> <20210508134726.GA11665@www5.open-std.org> <87y2co1zun.fsf@vps.thesusis.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87y2co1zun.fsf@vps.thesusis.net> User-Agent: Mutt/1.5.21 (2010-09-15) Precedence: bulk List-ID: X-Mailing-List: linux-raid@vger.kernel.org Phillip, et al -- ...and then Phillip Susi said... % % keld@keldix.com writes: % % > My understanding is that raid10 - all layouts - are really raid0 and % > then raid 1 on top. % % Naieve implementations work that way, and this is also why they require % a an even number of disks with 4 being the minimum. Linux raid10 is not % naieve and can operate with any number of disks >= 2. [snip] I've been chewing on this for a few days and I am STILL confused. Please help! :-) RAID10 is striping AND mirroring (leaving out for the moment the distinction of striping mirrors vs mirroring stripes). How can one have both with only two disks?? You either stripe the two disks together for more storage or mirror them for redundant storage, but I just don't see how one could do both. Thanks in advance :-) :-D -- David T-G See http://justpickone.org/davidtg/email/ See http://justpickone.org/davidtg/tofu.txt