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=-2.0 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 A011DC432C0 for ; Fri, 29 Nov 2019 00:44:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5C72021787 for ; Fri, 29 Nov 2019 00:44:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=gmx.net header.i=@gmx.net header.b="Py2SMxv3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726664AbfK2Ao3 (ORCPT ); Thu, 28 Nov 2019 19:44:29 -0500 Received: from mout.gmx.net ([212.227.15.15]:52671 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726582AbfK2Ao3 (ORCPT ); Thu, 28 Nov 2019 19:44:29 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1574988263; bh=/lffysegcLXjasZ+Il5ZT7X11aVfopGEPaf/Q2nOZw0=; h=X-UI-Sender-Class:Subject:To:References:From:Date:In-Reply-To; b=Py2SMxv3l75BBLEQmZhcobUxUoI6pGHIzxyvbq4FSpOJI2ctEEW50eSK7hS+8b2Sj vO9AVygx4c4zpKfmvuJXbLupIzZHDi/nYfWX2kKuuXJUhVyDckb50TvhF3H25XQX0L NY8sGGxGm3prpHbcJaPAE42xX8a7QprXpjHJgY2s= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [0.0.0.0] ([13.231.109.76]) by mail.gmx.com (mrgmx004 [212.227.17.184]) with ESMTPSA (Nemesis) id 1M42jK-1iaUOU2zs8-000765; Fri, 29 Nov 2019 01:44:23 +0100 Subject: Re: BTRFS subvolume RAID level To: waxhead@dirtcellar.net, Btrfs BTRFS References: <494b0df1-2aab-5169-836d-e381498f64db@dirtcellar.net> From: Qu Wenruo Autocrypt: addr=quwenruo.btrfs@gmx.com; prefer-encrypt=mutual; keydata= mQENBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAG0IlF1IFdlbnJ1byA8cXV3ZW5ydW8uYnRyZnNAZ214LmNvbT6JAU4EEwEIADgCGwMFCwkI BwIGFQgJCgsCBBYCAwECHgECF4AWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCXZw1oQAKCRDC PZHzoSX+qCY6CACd+mWu3okGwRKXju6bou+7VkqCaHTdyXwWFTsr+/0ly5nUdDtT3yEVggPJ 3VP70wjlrxUjNjFb6iIvGYxiPOrop1NGwGYvQktgRhaIhALG6rPoSSAhGNjwGVRw0km0PlIN D29BTj/lYEk+jVM1YL0QLgAE1AI3krihg/lp/fQT53wLhR8YZIF8ETXbClQG1vJ0cllPuEEv efKxRyiTSjB+PsozSvYWhXsPeJ+KKjFen7ebE5reQTPFzSHctCdPnoR/4jSPlnTlnEvLeqcD ZTuKfQe1gWrPeevQzgCtgBF/WjIOeJs41klnYzC3DymuQlmFubss0jShLOW8eSOOWhLRuQEN BFnVga8BCACqU+th4Esy/c8BnvliFAjAfpzhI1wH76FD1MJPmAhA3DnX5JDORcgaCbPEwhLj 1xlwTgpeT+QfDmGJ5B5BlrrQFZVE1fChEjiJvyiSAO4yQPkrPVYTI7Xj34FnscPj/IrRUUka 68MlHxPtFnAHr25VIuOS41lmYKYNwPNLRz9Ik6DmeTG3WJO2BQRNvXA0pXrJH1fNGSsRb+pK EKHKtL1803x71zQxCwLh+zLP1iXHVM5j8gX9zqupigQR/Cel2XPS44zWcDW8r7B0q1eW4Jrv 0x19p4P923voqn+joIAostyNTUjCeSrUdKth9jcdlam9X2DziA/DHDFfS5eq4fEvABEBAAGJ ATwEGAEIACYCGwwWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCXZw1rgUJCWpOfwAKCRDCPZHz oSX+qFcEB/95cs8cM1OQdE/GgOfCGxwgckMeWyzOR7bkAWW0lDVp2hpgJuxBW/gyfmtBnUai fnggx3EE3ev8HTysZU9q0h+TJwwJKGv6sUc8qcTGFDtavnnl+r6xDUY7A6GvXEsSoCEEynby 72byGeSovfq/4AWGNPBG1L61Exl+gbqfvbECP3ziXnob009+z9I4qXodHSYINfAkZkA523JG ap12LndJeLk3gfWNZfXEWyGnuciRGbqESkhIRav8ootsCIops/SqXm0/k+Kcl4gGUO/iD/T5 oagaDh0QtOd8RWSMwLxwn8uIhpH84Q4X1LadJ5NCgGa6xPP5qqRuiC+9gZqbq4Nj Message-ID: Date: Fri, 29 Nov 2019 08:44:18 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: <494b0df1-2aab-5169-836d-e381498f64db@dirtcellar.net> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="234ovL1ttQKLA5VwdJMU2mbjGv34vCAqk" X-Provags-ID: V03:K1:zKsIvziL4Odirq/+xBYwNaB59lL8L7Vsb0FXEE8ZB9zD1fW0wJC e4Yahki6RI/4ghURuMKfsi5Ef3I+yWNXax+IWbBqWJyQmC+mRj9IJLbqnLXbkCmWMDe2UJN sMAC+pSBHNGEcZGIQerdGmXWfYQ/Tu8TNGbEkf8w3dPtCMgpzOKMzngra3D/+h5XAdSqGby wUU4pKcwsOHSK74G11Gfg== X-UI-Out-Filterresults: notjunk:1;V03:K0:/wsQdJ73XDM=:cFy3Je/D3VgisvwY1qJgft g3hMXss9SvNPWd7RW8SBZKLARHGhRDP2dVbXJBQp4miE9+OkzbpwTqZQJhCkbjxvRDxGRUmGQ o86K6ofiQ6yN+w+nIgtcYfZHJsYPFL6UkFfswqAozjRp9W81LnaFH93eHVujzpk3/7JXVgiMn +PyvaV3I4lgytSCk5LWhZkGRgzspBLQjxhskoacGqZDUJZbWCnQD6B82Md0fKJdVO1JrKJhCe PGfsfI5SNR0PkctkjQt+XdcaNmBi3zLhKt9cocplwRJH1NUZTtJiLYFk3BAHzyn2NVvBsVkwA 9QvKW8AVqnsxcQOEWtTBbqVjtq70Dx38RSko3srW4FZGaer/Cv4sikYCf6mPswJGKtc7swKC2 F+mGFpZA5yFS1aKlQobHPyC/sJ9oQAsehlpmcoDL8y5Y1Ly0xWqUhA4v6YhHt0VF7yChOsMp5 fazP8IO7f63GYws8n5u28Lwzfau73RIG4b6qgfiwOWXLGtrPDr5ZiIJ7VT3dtEhN1eM7VZvXC GbWsLVtKugrmp5hTbsg1IALi/RpabPavVoSLLhdANoImxlLvFBHksEyz7RwNjYBi5og2rdLNO 4VZwrrNJKBvSLza1fhgpLaBxIPWCzebhFr+pJTTymM6w23HgBRBGb3rXjXpD5ADMRaafYGDHd 1wZ/qKXL6HLZoJl6B8RldFQO+JyT+Dcm+QMVaVJuj2ZCxdvho1LsvW+YQOqZ63ANPGPgr6qjd ToOiQuwhJGxfAQ6DAQVRZY6/bkbYqxTKqN4l9dzOMN+9+0GzWzjMpWXul05+8LCUrsjGaKqaB G5wlINZLvCDwGRf0KQuKupOsNjYOekIsggpdzApKXN6+bUhgK0r9SKx0aISVS7Lh3lBcLvB2J LRPFGvuuodKD7G2Cnm6fiyaC0+UJ8Zsiy3IN4b/Fl0K92pGh3THzPnxtKo4eCUW2u0kr6oMHd 90xfbQWxn30FtSrMG7AiGDm7Q133anNW3hDL/yHAlpGkWjVrPqeyPlHFnVjaPZvmPCXw0BBdT dEMHklZLQp9rce1TJTF/tunbOqoVfUVlMxcbyidMy49TNeG18i6Jaj2zh2/i8bQHvaeshNEiL mLxCbylPN/XHjRM6cuFMiSd4rHgM4E9IPSnm/Gf+c7mSnGw+nDh14C+Ar1xVm49abxvxzJT5d j/Uowk+QY3wfjD0xjfhprhEB72M/hIIvVB8Mps+uQn+ZihTmIoPuEC0ftCYkdl49MQiWYniHK 1RzLMg3NAXYOhpwe1NJGX2U7EzUQMnrOxYR79lzXw+IbpexTqwclj8X2HhTo= 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) --234ovL1ttQKLA5VwdJMU2mbjGv34vCAqk Content-Type: multipart/mixed; boundary="UhYLy1JObTqQwOKkkltN0tUxOBuITmv2L" --UhYLy1JObTqQwOKkkltN0tUxOBuITmv2L Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 2019/11/29 =E4=B8=8A=E5=8D=886:48, waxhead wrote: > Just out of curiosity.... >=20 > What are the (potential) show stoppers for implementing subvolume RAID > levels in BTRFS? This is more and more interesting now that new RAID > levels has been merged (RAID1c3/4) and RAID5/6 is slowly inching toward= s > usable status. My quick guesses are: - Subvolume and RAID aware extent allocator Current extent allocator cares nothing about who is requesting the extent. It cares a little about the RAID profile (only for convert). We need some work here at least. - Way to prevent false ENOSPC due to profile restriction If subvolume is using some exotic profile, while extent/csum tree is using regular profile, and subvolume eats too many space, making it impossible to fit extent in their desired profile. We will got ENOSPC and even goes RO. Thanks, Qu >=20 > I imagine that RAIDc4 for example could potentially give a grotesque > speed increase for parallel read operations once BTRFS learns to > distribute reads to the device with the least waitqueue / fastest devic= es. --UhYLy1JObTqQwOKkkltN0tUxOBuITmv2L-- --234ovL1ttQKLA5VwdJMU2mbjGv34vCAqk Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEELd9y5aWlW6idqkLhwj2R86El/qgFAl3gaeIACgkQwj2R86El /qhHvggAon+T2jw/21EmVbPFePZk7vJZBNkmWhMKRAdU+qNHn7sgewCmNPzD8AYa vr/5+9O7ddUWLdvhjE+86n+xfYWWNvFXq/XuhBvDKoG7Ov+BvyALMIGmt48WbM/6 YvM+F8Imo3GKBUIstiOpxZZWNF5MW/A9x/FRIJgeJaCmpTRZVdDUz3RmDWrqjG6A LXWGnO6F97eT0v4YLeK6y79tlaTB5kcWTE81KDNGld+f77AYUd/7bvls95q7S2I0 MKbzAkbP3YnWxdJAV0Ic0En4ofjXV1q6lQdEmLD1/WyMwsNsf6/vNfuvKqKBGyvI vHPSXcjgbftLjvoz8oVzDGMB/mCG2w== =Mv7I -----END PGP SIGNATURE----- --234ovL1ttQKLA5VwdJMU2mbjGv34vCAqk--