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Thu, 7 Feb 2019 16:21:57 -0500 (EST) Subject: Re: btrfs as / filesystem in RAID1 To: linux-btrfs References: <33679024.u47WPbL97D@t460-skr> <92ae78af-1e43-319d-29ce-f8a04a08f7c5@mendix.com> <2159107.RxXdQBBoNF@t460-skr> From: Remi Gauvin Openpgp: url=http://www.georgianit.com/pgp/Remi%20Gauvin%20remi%40georgianit.com%20(0xEF539FF247456A6D)%20pub.asc Autocrypt: addr=remi@georgianit.com; prefer-encrypt=mutual; keydata= mQENBFogjcYBCADvI0pxdYyVkEUAIzT6HwYnZ5CAy2czT87Si5mqk4wL4Ulupwfv9TLzaj3R CUgHPNpFsp1n/nKKyOq1ZmE6w5YKx4I8/o9tRl+vjnJr2otfS7XizBaVV7UwziODikOimmT+ sGNfYGcjdJ+CC567g9aAECbvnyxNlncTyUPUdmazOKhmzB4IvG8+M2u+C4c9nVkX2ucf3OuF t/qmeRaF8+nlkCMtAdIVh0F7HBYJzvYG3EPiKbGmbOody3OM55113uEzyw39k8WHRhhaKhi6 8QY9nKCPVhRFzk6wUHJa2EKbKxqeFcFzZ1ok7l7vrX3/OBk2dGOAoOJ4UX+ozAtrMqCBABEB AAG0IVJlbWkgR2F1dmluIDxyZW1pQGdlb3JnaWFuaXQuY29tPokBPgQTAQIAKAUCWiCNxgIb IwUJCWYBgAYLCQgHAwIGFQgCCQoLBBYCAwECHgECF4AACgkQ71Of8kdFam2V1Qf9Fs6LSx1i OoVgOzjWwiI06vJrZznjmtbJkcm/Of5onITZnB4h+tbqEyaMYYsEIk1r4oFMfKB7SDpQbADj 9CI2EbpygwZa24Oqv4gWEzb4c7mSJuLKTnrhmwCOtdeDQXO/uu6BZPkazDAaKHUM6XqNEVvt WHBaGioaV4dGxzjXALQDpLc4vDreSl9nwlTorwJR9t6u5BlDcdh3VOuYlgXjI4pCk+cihgtY k3KZo/El1fWFYmtSTq7m/JPpKZyb77cbzf2AbkxJuLgg9o0iVAg81LjElznI0R5UbYrJcJeh Jo4rvXKFYQ1qFwno1jlSXejsFA5F3FQzJe1JUAu2HlYqRrkBDQRaII3GAQgAo0Y6FX84QsDp R8kFEqMhpkjeVQpbwYhqBgIFJT5cBMQpZsHmnOgpYU0Jo8P3owHUFu569g6j4+wSubbh2+bt WL0QoFZcng0a2/j3qH98g9lAn8ZgohxavmwYINt7b+LEeDoBvq0s/0ZeXx47MOmbjROq8L/g QOYbIWoJLO2emyxmVo1Fg00FKkbuCEgJPW8U/7VX4EFYaIhPQv/K3mpnyWXIq5lviiMCHzxE jzBh/35DTLwymDdmtzWgcu1rzZ6j2s+4bTxE8mYXd4l2Xonn7v448gwvQmZJ8EPplO/pWe9F oISyiNxZnQNCVEO9lManKPFphfVHqJ1WEtYMiLxTkQARAQABiQElBBgBAgAPBQJaII3GAhsM BQkJZgGAAAoJEO9Tn/JHRWptnn0H+gOtkumwlKcad2PqLFXCt2SzVJm5rHuYZhPPq4GCdMbz XwuCEPXDoECFVXeiXngJmrL8+tLxvUhxUMdXtyYSPusnmFgj/EnCjQdFMLdvgvXI/wF5qj0/ r6NKJWtx3/+OSLW0E9J/gLfimIc3OF49E3S1c35Wj+4Okx9Tpwor7Tw8KwBVbdZA6TyQF08N phFkhgnTK6gl2XqIHaoxPKhI9pKU5oPkg2eI27OICZrpTCppaSh3SGUp0EHPkZuhVfIxg4vF nato30VZr+RMHtPtx813VZ/kzj+2pC/DrwZOtqFeaqJfCi6JSik3vX9BQd9GL4mxytQBZKXz SY9JJa155sI= Message-ID: Date: Thu, 7 Feb 2019 16:21:56 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="RvurNLonvN1RukS2En5hyV6jLxQrY3B6b" 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) --RvurNLonvN1RukS2En5hyV6jLxQrY3B6b Content-Type: multipart/mixed; boundary="gLdRJifIV9TQifhh2RcdtHasiVIjPIjRV"; protected-headers="v1" From: Remi Gauvin To: linux-btrfs Message-ID: Subject: Re: btrfs as / filesystem in RAID1 References: <33679024.u47WPbL97D@t460-skr> <92ae78af-1e43-319d-29ce-f8a04a08f7c5@mendix.com> <2159107.RxXdQBBoNF@t460-skr> In-Reply-To: --gLdRJifIV9TQifhh2RcdtHasiVIjPIjRV Content-Type: multipart/mixed; boundary="------------CB5D2C0C9A2FA8611E6CE9DA" Content-Language: en-US This is a multi-part message in MIME format. --------------CB5D2C0C9A2FA8611E6CE9DA Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 2019-02-07 2:39 p.m., Austin S. Hemmelgarn wrote: > Again, BTRFS mounting degraded is significantly riskier than LVM or MD > doing the same thing.=C2=A0 Most users don't properly research things (= When's > the last time you did a complete cost/benefit analysis before deciding > to use a particular piece of software on a system?), and would not know= > they were taking on significantly higher risk by using BTRFS without > configuring it to behave safely until it actually caused them problems,= > at which point most people would then complain about the resulting data= > loss instead of trying to figure out why it happened and prevent it in > the first place.=C2=A0 I don't know about you, but I for one would rath= er > BTRFS have a reputation for being over-aggressively safe by default tha= n > risking users data by default. Another important consideration is that BTRFS has practically zero tolerance for corruption in the metadata. Most other FS's can, at least on surface appearance, either continue working despite bits of scrambled data, or have repair utilities that are pretty good at figuring out what the scrambled data should be and make a best guess effort that more or less works (leaving aside for now statistics as to how often that might cause undetected data corruption, which possibly propagates to backups et= c.) BTRFS is almost entirely reliant on the Duplicate copy of metadata, which is missing when running degraded. It makes it much more likely for simple error to break the FS entirely. BTRFS default configuration prioritizes data integrity over uptime, and I think a very good argument can be made for any FS that *should* be the default. --------------CB5D2C0C9A2FA8611E6CE9DA Content-Type: text/x-vcard; charset=utf-8; name="remi.vcf" Content-Transfer-Encoding: quoted-printable Content-Disposition: attachment; filename="remi.vcf" begin:vcard fn:Remi Gauvin n:Gauvin;Remi org:Georgian Infotech adr:;;3-51 Sykes St. N.;Meaford;ON;N4L 1X3;Canada email;internet:remi@georgianit.com tel;work:226-256-1545 version:2.1 end:vcard --------------CB5D2C0C9A2FA8611E6CE9DA-- --gLdRJifIV9TQifhh2RcdtHasiVIjPIjRV-- --RvurNLonvN1RukS2En5hyV6jLxQrY3B6b Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAEBCAAGBQJcXKF0AAoJEO9Tn/JHRWpt8LIH+wc2keUwhKQ9GU7OGsybHtKp 2Vgq7dKiy4XEz7zLrWMOeDaMmJBAgNGtgCns5xrTKmqKtD0MJz2ix4bXWXFBU6Mj WVziBCmYXQr5hicCwKQnK0VWY02gX4gnvIWm4efGK/jJVed5OZIkeyhdzJ/Nyya9 4bjQeYD1jxy9surkZJZCCv95k9AmSkVp8S423J4FlCcVXGcPFO7jDTsdjDu8j08W fEULjRrT7L3JkJskZ0DA6yLWg63S+SjiV6zpadgQ24InVDO8dgOlW0q3kUMIi9VP duL3CoS7jinteXwA5SImK7Net36ZHPRbJxKVmZImC+/IblpHmUgr8YsYIURZTFk= =o/V/ -----END PGP SIGNATURE----- --RvurNLonvN1RukS2En5hyV6jLxQrY3B6b--