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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 77216C2BA15 for ; Sat, 4 Apr 2020 21:15:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 45CB0206E6 for ; Sat, 4 Apr 2020 21:15:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726461AbgDDVPr (ORCPT ); Sat, 4 Apr 2020 17:15:47 -0400 Received: from mx2.suse.de ([195.135.220.15]:49836 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726388AbgDDVPr (ORCPT ); Sat, 4 Apr 2020 17:15:47 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id E4A69AB5C; Sat, 4 Apr 2020 21:15:44 +0000 (UTC) From: NeilBrown To: Zygo Blaxell , Andrea Gelmini Date: Sun, 05 Apr 2020 07:15:38 +1000 Cc: Qu Wenruo , fdmanana@gmail.com, linux-btrfs Subject: Re: RAID5/6 permanent corruption of metadata and data extents In-Reply-To: <20200404145846.GK13306@hungrycats.org> References: <7b4f5744-0e22-3691-6470-b35908ab2c2c@gmx.com> <20200402211415.GH13306@hungrycats.org> <20200404145846.GK13306@hungrycats.org> Message-ID: <87zhbrvtol.fsf@notabene.neil.brown.name> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org --=-=-= Content-Type: text/plain On Sat, Apr 04 2020, Zygo Blaxell wrote: > mdadm does one thing very well, but only the one thing. I don't imagine > Neil would extend mdadm to the point where it can handle handle silent You are correct, I wouldn't. md provides a block devices, btrfs provides a filesystem. They are totally different things. Saying that btrfs/RAID6 is "better" than mdadm/raid6 is like saying the ext4 is "better" than a SCSI drive. It doesn't really mean anything. I could argue that calling what btrfs does "RAID6" is misleading and possibly the cause of confusion. I think the decision to call what ZFS does "RAID-Z" was probably a good idea - it is somewhat like RAID, but on a whole new level. Maybe the stuff btrfs does could be RAID-B :-) NeilBrown --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEG8Yp69OQ2HB7X0l6Oeye3VZigbkFAl6I+PoACgkQOeye3VZi gblMpRAAnORWw2HCOy4ZcfrSOyBEYgLxZQ//bvxE0uDB0xpH9Nr80pQqV4rDp6oy kA6Majv6pSSFaVGbshdSG0bsNKDBzetMP48IYnJdkl1dh6vf7rFsCzRe4/RJBw8D 0+v2unnkCZG+AI1Wu3hRB9J5giNTasD904PriM0L9N5ZI3SErvLWZTvMMYcfG7NK B/H6ewD74JgiLbTsh18ya/Q1581sijlHRixkBOTX2DVrMY2fUNlALzhmtWjC4P/B KM/jl8sF+rwx6ypBbDZEwkDmeQMdEBbcYC75gNmnCbsEZKLCj15R/TX07n+oo5kZ CULessyZKbcRNJeynjQlxIRMbVYO8Wxbjcy0UcGdJwt7rSY1KWSEg0WkZhv2Fb9W WQgpQFLUBA8pMDeNLaHIgvdwjw3TA5JxlyBE5WP42Nqsyv2hRaJNr+LYRll33wZS bjzhPl2McsUhV0neUwebjKpZPPyqe2DmVY5udu0n07xRD42374E1D/ke82k0guiB qTl/lnrcPpao2j4GV0WZSpHKWGnDXEF5nAyno3r5y1npDVTS5d0KNGXdMXyBEURG Umt5Pcwf6JP15TWmwMbvqckxXQptyjmnS1fryx81fj1FQWsf6ubeS2yWKXGUFgcT eKQbSNcvnInlVYltmRw473SxxJ2LVd+t3HQ3k7AJzZRepFgrptk= =GWVy -----END PGP SIGNATURE----- --=-=-=--