From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by finch.gentoo.org (Postfix) with ESMTPS id 3CCEA138350 for ; Sun, 3 May 2020 14:28:07 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 0EBB3E09E2; Sun, 3 May 2020 14:27:58 +0000 (UTC) Received: from mail-qt1-f195.google.com (mail-qt1-f195.google.com [209.85.160.195]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 76BB4E094E for ; Sun, 3 May 2020 14:27:57 +0000 (UTC) Received: by mail-qt1-f195.google.com with SMTP id s30so11865858qth.2 for ; Sun, 03 May 2020 07:27:57 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:reply-to:message-id :date:user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=+AR2yZrDv6jXuyygH6Rf1Utk9qtX1w76gJaetZXIhek=; b=i2zChYwsC4IinStkoL/pdfST4xn5Iv9WCmDV8A/FegfCOIYOgPZvhsaPftD4llgmzt PNqjUyCASgaYNa+YBaTAi/m9w28DCVHtBDLqOgzFJdU9MPr7coxBZgW2EjEXUHIo/C9W a9g5hwk2jwO4Yi8Tb8AOHIUsh7sTv96Qz8u1caQnCqy3TxF1l9ltkyiJCbQ0YTzFlLvF KXRdOSXFJObRSYLl7qcbnesDJ0LJGqR3Oa3i+Qc3b6Qp/UExyOw81BvK4lZHPGL4OVAJ x1zw6z9wJsl+hfgz/Fi0t1ghDvWnpTDOFEAH9X3lVZive6hZcffKwN57hhWosiyBST+H jd0A== X-Gm-Message-State: AGi0PuZtsFd2GqTil+QbBSqMawWmSoAVBy2KW6q1Vq1MsX2DkpcL6zqq 20mPzAH+G5W55uyipm4AreQ+PwIRGow= X-Google-Smtp-Source: APiQypKn/sIXZNNF72L7dIN2wmrn4cnlkNGtRNyvGgAIKPA9jBlY7d/GykwwGDPPdmPcd9sn8MS6gA== X-Received: by 2002:ac8:6757:: with SMTP id n23mr12655895qtp.304.1588516076479; Sun, 03 May 2020 07:27:56 -0700 (PDT) Received: from [192.168.1.18] (c-76-23-130-96.hsd1.ct.comcast.net. [76.23.130.96]) by smtp.gmail.com with ESMTPSA id t15sm8404551qtc.64.2020.05.03.07.27.55 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 03 May 2020 07:27:56 -0700 (PDT) Subject: Re: [gentoo-user] which linux RAID setup to choose? To: gentoo-user@lists.gentoo.org References: From: Jack Message-ID: <2251dac1-92cd-7c3b-97ea-6a061fe01eb0@users.sourceforge.net> Date: Sun, 3 May 2020 10:27:54 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org X-Auto-Response-Suppress: DR, RN, NRN, OOF, AutoReply MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US-large X-Archives-Salt: 98a3022b-4648-41b0-8446-670332c48b47 X-Archives-Hash: 016bac99a750d37c95ee12251082e79d On 5/3/20 1:44 AM, Caveman Al Toraboran wrote: > [snip]... > so, we get the following combinations of > disk failures that, if happen, we won't > lose any data: > > RAID0 > ------^------ > RAID1 RAID1 > --^-- --^-- > F . . . < cases with > . F . . < single disk > . . F . < failures > . . . F < > > F . . F < cases with > . F F . < two disk > . F . F < failures > F . F . < > . F F . < > > this gives us 4+5=9 possible disk failure > scenarious where we can survive it without > any data loss. Minor point - you have one duplicate line there ". f  f ." which is the second and last line of the second group.  No effect on anything else in the discussion. Trying to help thinking about odd numbers of disks, if you are still allowing only one disk to fail, then you can think about mirroring half disks, so each disk has half of it mirrored to a different disk, instead of drives always being mirrored in pairs.