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, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,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 918EBC433FF for ; Wed, 31 Jul 2019 06:58:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4854320693 for ; Wed, 31 Jul 2019 06:58:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=gmx.net header.i=@gmx.net header.b="N9o/RdbE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727809AbfGaG6S (ORCPT ); Wed, 31 Jul 2019 02:58:18 -0400 Received: from mout.gmx.net ([212.227.17.21]:49855 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727628AbfGaG6Q (ORCPT ); Wed, 31 Jul 2019 02:58:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1564556288; bh=7U4w2Jr2ENv3S9lH0F9LY2460WXVPOhBdodljpknsAY=; h=X-UI-Sender-Class:Subject:To:References:From:Date:In-Reply-To; b=N9o/RdbEBI8Z2J/QoAzuw4ZS63X1i7LxuOWmM3GA7OcH1ED9zByN5LWQswPhxUWrB AErphU36hF/YjVYxoKRHnEA1D1wsZG5/uJ3z2FMzLilv3p5zZxk4CzKDCemC/3y1qc CKXoTUrqGJO+APGmOvP0/tLupY/kfevOUFgp3S4A= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [0.0.0.0] ([54.250.245.166]) by mail.gmx.com (mrgmx104 [212.227.17.174]) with ESMTPSA (Nemesis) id 1MOzOm-1hirhr1shY-00PPZv; Wed, 31 Jul 2019 08:58:08 +0200 Subject: Re: [PATCH] btrfs: Allow more disks missing for RAID10 To: dsterba@suse.cz, Qu Wenruo , linux-btrfs@vger.kernel.org References: <20190718062749.11276-1-wqu@suse.com> <20190725183741.GX2868@twin.jikos.cz> <20190726103902.GZ2868@twin.jikos.cz> From: Qu Wenruo Openpgp: preference=signencrypt Autocrypt: addr=quwenruo.btrfs@gmx.com; prefer-encrypt=mutual; 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Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190726103902.GZ2868@twin.jikos.cz> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="VgPshRbJHuXnbYX7MKKZYNeLAmiLiM9V4" X-Provags-ID: V03:K1:rpEp9rlZB70gmYKE1Wo0ru1Nolp6EHtLK7xvgrrRxrsGX4xjmms XJUO4DrftZfR87kZqtg/zlq1k6E0pw4qgyaOIjrp58DsKVC1C8cFE015ZVNQRMNIx/8lUhG Uu8Zznqr2o9a26PZaAK2y6qtJqdSxPx8sEAVIfyXXQnAOy1/pCD/BFOODENaSo1NaZ/KSxU 4Wz1rqjR/FOSx87vkg4JA== X-UI-Out-Filterresults: notjunk:1;V03:K0:iHLSD6Q+SsE=:d5pyKZce0Z5+3Eoblk/1Op K4gQ8aO7f+dXO1VI8MhJ77aRgrl0I7O8mBhkDlo8rGr80bmZllHWC9iqopwM+3mwvHamQ0NGg gwE7rnXer1ZDKiWctgLEFonxUMRwKSBG6hVhkK+WGoZnTaUxultDcxOv9KPVexqGdGXQ/gFg9 vdJENYuYPTyUTDTVm0unWL4qrAzFl+X5dmEX9B91B6zVdCtdTYW4Ua+c7RCd8XKrLuggG7zMF KbVlWg+NcPowHGazLrrYqqG9SyXwnB5pk3LronAzrhTRaR52xK+IJyWi8GzFaSANWmc1RnvXI 5IxXVgjFLndw6tHhsYoWmUGRoYG4QMOejN63pnX9NMGXzX82ax/jIWHkdbC4WxGD14mBW09Rq gFD12novVSOP7lc0fb+AysGVFQhKttYzDDWNS7B7QqNe5hfbWFopcISk82pcHCc3YPny+eFiL xc3aZgcCZns91nRHGdQVkbTuSkbTy45RNee4pjk/Z8YZ0nduiuZkEs3I6eAIj8D9cqnzvCK4B 7RygMKCryy8azW827deW1ZHFl4p5QdDGhrHvmahRYNpm85cAK9YBDQAVDIz0463v+TpE5euXj n5aeEAAKHjthL0qmigGoE472IgZeI5sXvGKbZWlR31+DYlW+WOBC0ifKNgWHePeKbK5wfLKep ew/rTvK4jcKuOmVn98obY3mA8UL8qySMWRLvcCbd1l9Wgs9hdWWS+4uqcfA4JH+gUiiMshblG SCG9JYTN85nx2/lgc2LQrCqXbjV8T1UqylQmFWrqLe1I8jzbgThvo/QFbbW79Zg9MJNPQvNSL DU2UQt6nYx6rxQ9qZjMvndNrhWF6fAjWiCdPpWNVgVS8EF69gkLCUkkest82i3CQwjkJLakLT Ysa4otMNUAK/wBEPXtyvJlBtwHxZi5ZU3RsQiA9tukdDhukedmjbcP6dQKCGhPEC0KcDRkhlh O+FkBZ1BWNg4PPJlD/zI2FYqPtqmDl2X1U2H2wWDzUc4N72WYEU25k5Ocn5aKOybDVSFdDTrc 9JDZ8AtfiD6BDbu8Adg9PJxk61OgrFmM0wSoV6Gc3H0y/wTGS1EhS9uhxwoWWwohMRxEKbHiO 3kn0SGGz5Y3FhU= Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --VgPshRbJHuXnbYX7MKKZYNeLAmiLiM9V4 Content-Type: multipart/mixed; boundary="wwQ2CWrKxcLZIwqZuBfltPv1EmBU2pD10"; protected-headers="v1" From: Qu Wenruo To: dsterba@suse.cz, Qu Wenruo , linux-btrfs@vger.kernel.org Message-ID: <052a23bb-428d-3249-d8cb-b508ebca0b62@gmx.com> Subject: Re: [PATCH] btrfs: Allow more disks missing for RAID10 References: <20190718062749.11276-1-wqu@suse.com> <20190725183741.GX2868@twin.jikos.cz> <20190726103902.GZ2868@twin.jikos.cz> In-Reply-To: <20190726103902.GZ2868@twin.jikos.cz> --wwQ2CWrKxcLZIwqZuBfltPv1EmBU2pD10 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 2019/7/26 =E4=B8=8B=E5=8D=886:39, David Sterba wrote: > On Fri, Jul 26, 2019 at 07:41:41AM +0800, Qu Wenruo wrote: >> >> >> On 2019/7/26 =E4=B8=8A=E5=8D=882:37, David Sterba wrote: >>> On Thu, Jul 18, 2019 at 02:27:49PM +0800, Qu Wenruo wrote: >>>> RAID10 can accept as much as half of its disks to be missing, as lon= g as >>>> each sub stripe still has a good mirror. >>> >>> Can you please make a test case for that? >> >> Fstests one or btrfs-progs one? >=20 > For fstests. OK, that test case in fact exposed a long-existing bug, we can't create degraded chunks. So if we're replacing the missing devices on a 4 disk RAID10 btrfs, we will hit ENOSPC as we can't find 4 devices to fulfill a new chunk. And it will finally trigger transaction abort. Please discard this patch until we solve that problem. Thanks, Qu >=20 >>> I think the number of devices that can be lost can be higher than a h= alf >>> in some extreme cases: one device has copies of all stripes, 2nd copy= >>> can be scattered randomly on the other devices, but that's highly >>> unlikely to happen. >>> >>> On average it's same as raid1, but the more exact check can potential= ly >>> utilize the stripe layout. >>> >> That will be at extent level, to me it's an internal level violation, >> far from what we want to improve. >=20 > Ah I don't mean to go the extent level, as you implemented it is enough= > and an improvement. >=20 --wwQ2CWrKxcLZIwqZuBfltPv1EmBU2pD10-- --VgPshRbJHuXnbYX7MKKZYNeLAmiLiM9V4 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEELd9y5aWlW6idqkLhwj2R86El/qgFAl1BO/oACgkQwj2R86El /qh0ewf+PvEkF1yN7s0PSzpFeaLnUDY5DsfDseO1gWOzOlK6a9TSh538DMXyLkoe pJFlh8fRP5naViF86PfSXJNHu/x3uCkj1BHz2gBEVp3QrPBheMk8LDyGCVrv/bg0 ZCkbtuBPhjEFx+FOU/ONQfuxovmbLQTcinzAz92MbjTLxxiP82uF2DLT4WkjUUuX Scr2kcliBIbkWVxQaBETFH9EpehZe5TznVznukMMsBWfSNh5bdkhozN5UvPpEJPT wIi6qmr2Gf/A7bARuUlCH3aVNiEzfUISsdFBtOVq+7J6wffeWbrb86vMUs1UxaQ1 7e3XgwgqvrO5PjLWxSHP+kMgvAGvrw== =di48 -----END PGP SIGNATURE----- --VgPshRbJHuXnbYX7MKKZYNeLAmiLiM9V4--