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=-2.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, 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 291B5FA3728 for ; Wed, 16 Oct 2019 15:40:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F265F218DE for ; Wed, 16 Oct 2019 15:40:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=liland-com.20150623.gappssmtp.com header.i=@liland-com.20150623.gappssmtp.com header.b="I4EmlGF1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404538AbfJPPkP (ORCPT ); Wed, 16 Oct 2019 11:40:15 -0400 Received: from mail-wm1-f51.google.com ([209.85.128.51]:35935 "EHLO mail-wm1-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727929AbfJPPkO (ORCPT ); Wed, 16 Oct 2019 11:40:14 -0400 Received: by mail-wm1-f51.google.com with SMTP id m18so3298400wmc.1 for ; Wed, 16 Oct 2019 08:40:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=liland-com.20150623.gappssmtp.com; s=20150623; h=to:from:subject:message-id:date:user-agent:mime-version :content-transfer-encoding:content-language; bh=34o9j1zSktGtBupQXhHUPymaQoRhq/kdv25PyWS5f/8=; b=I4EmlGF1ykPeBNP/ze7aRKLLo/z44SZN/E2dbOsKftHZk6VUdPPA847xrcuNRnfB0T C+ypQ3SPbuWCa4oy62gVwtZXX4+UqQBW5jfLnFoV7dvMubnFRugOnJAdmv/DImXa3uPO i6pfzLN2q8aGBNAfcrb0yV6Nmjgad6s1W24Uaqr4hPAO3a6d8RQKarSDFiOBebLxgi8r 2MTEdapkai5yyCaVqwu1ZjD0aSMgIv5YOvtEoVq0CmqblJUhl5ui+x2lNCnx2shnntdS 1zVWo7h93STMjuTOy2LKOy3JrfTUONSZN1MEy2KprDm7gv0i2jtYTW5DspS0adMxwH0A 7+ww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:to:from:subject:message-id:date:user-agent :mime-version:content-transfer-encoding:content-language; bh=34o9j1zSktGtBupQXhHUPymaQoRhq/kdv25PyWS5f/8=; b=A8HYLyvGUCY3OrPPg/iN2uamWbbirftm/ZMuZYroMsHjtpvn9JBpdXjkaVxUIJ+MhJ XCGL+aa2uB+yfV1kNK3kDjin+HiegtOQ4rikvW2PsBsi57RC21U10KKLX9OAgenPE0x0 Z1tl4Bjz8aigxRtau3JhOaisFWhicDlCcETBBufHniEPQgp8BNjmSU6VwF1PYXJ7COwD ifSPK+nob4cntJiM/vvCCDqUtGXX5HF+1RMVvsiJGRj6COU+sf+XjDYnHFNoAK5kdWyk cyIHPjCl0nhB370xSgsQyvpNCyxPYP21JP7DLcgvhXWYUzOeNN34zzxpd1QAmIPXpHQP QjlA== X-Gm-Message-State: APjAAAVrHiH1thnk0pautAsLnBmcZpcSlcrX7cT9WrWa5PDsKJKqIWlH Ya05bMg0KHMWgT1eUcXj3Qfil+6L1F3shnHjOCg59uVCdFlSpQ+qnE1KDcANAVA8Vq03JkZlfuJ T1wSU+/pQZaTFq/YdyGY/O0Yu X-Google-Smtp-Source: APXvYqzEhuXVgG9qRBW8Jdp8NRndAhr/BQpBWpWUl8ADdCnHJGn78+6IvYbuj0QN49waEqNMbFb+Jw== X-Received: by 2002:a1c:770f:: with SMTP id t15mr3693630wmi.136.1571240412451; Wed, 16 Oct 2019 08:40:12 -0700 (PDT) Received: from [192.168.0.121] ([62.218.42.35]) by smtp.gmail.com with ESMTPSA id s13sm3121055wmc.28.2019.10.16.08.40.11 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 16 Oct 2019 08:40:11 -0700 (PDT) To: linux-btrfs@vger.kernel.org From: Edmund Urbani Subject: MD RAID 5/6 vs BTRFS RAID 5/6 Message-ID: Date: Wed, 16 Oct 2019 17:40:10 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en-GB Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Hello everyone, having recovered most of my data from my btrfs RAID-6, I have by now migrat= ed to mdadm RAID (with btrfs on top). I am considering switching back to btrfs RA= ID some day, when I feel more confident regarding its maturity. I put some thought into the pros and cons of this choice that I would like = to share: btrfs RAID-5/6: - RAID write hole issue still unsolved (assuming https://btrfs.wiki.kernel.org/index.php/RAID56 is up-to-date) + can detect and fix bit rot + flexibility (resizing / reshaping) - maturity ? (I had a hard time recovering my data after removal of a drive= that had developed some bad blocks. That's not what I would expect from a RAID-6 setup. To be fair I should point out that I was running kernel 4.14 at the = time and did not do regular scrubbing.) btrfs on MD RAID 5/6: + options to mitigate RAID write hole - bitrot can only be detected but not fixed + mature and proven RAID implementation (based on personal experience of replacing plenty of drives over the years without data loss) I would be interested in getting your feedback on this comparison. Do you a= gree with my observations? Did I miss anything you would consider important? Regards, =C2=A0Edmund --=20 *Liland IT GmbH* Ferlach =E2=97=8F Wien =E2=97=8F M=C3=BCnchen Tel: +43 463 220111 Tel: +49 89=20 458 15 940 office@Liland.com https://Liland.com =C2=A0 Copyright =C2=A9 2019 Liland IT GmbH=C2=A0 Diese Mail enthaelt vertrauliche und/oder=20 rechtlich geschuetzte=C2=A0Informationen.=C2=A0 Wenn Sie nicht der richtige Adressat=20 sind oder diese Email irrtuemlich=C2=A0erhalten haben, informieren Sie bitt= e=20 sofort den Absender und vernichten=C2=A0Sie diese Mail. Das unerlaubte Kopi= eren=20 sowie die unbefugte Weitergabe=C2=A0dieser Mail ist nicht gestattet.=C2=A0 This=20 email may contain confidential and/or privileged information.=C2=A0 If you are=20 not the intended recipient (or have received this email in=C2=A0error) plea= se=20 notify the sender immediately and destroy this email. 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