Date: Thu, 11 Aug 2016 13:02:35 +0200 From: Julien Cigar <julien@perdition.city> To: Borja Marcos <borjam@sarenet.es> Cc: freebsd-fs@freebsd.org, Jordan Hubbard <jkh@ixsystems.com> Subject: Re: HAST + ZFS + NFS + CARP Message-ID: <20160811110235.GN70364@mordor.lan> In-Reply-To: <20160811101539.GM70364@mordor.lan> References: <65906F84-CFFC-40E9-8236-56AFB6BE2DE1@ixsystems.com> <B48FB28E-30FA-477F-810E-DF4F575F5063@gmail.com> <61283600-A41A-4A8A-92F9-7FAFF54DD175@ixsystems.com> <20160704183643.GI41276@mordor.lan> <AE372BF0-02BE-4BF3-9073-A05DB4E7FE34@ixsystems.com> <20160704193131.GJ41276@mordor.lan> <E7D42341-D324-41C7-B03A-2420DA7A7952@sarenet.es> <20160811091016.GI70364@mordor.lan> <1AA52221-9B04-4CF6-97A3-D2C2B330B7F9@sarenet.es> <20160811101539.GM70364@mordor.lan>
next in thread | previous in thread | raw e-mail | index | archive | help
--yAzUYvkKIfeS0jQX Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Aug 11, 2016 at 12:15:39PM +0200, Julien Cigar wrote: > On Thu, Aug 11, 2016 at 11:24:40AM +0200, Borja Marcos wrote: > >=20 > > > On 11 Aug 2016, at 11:10, Julien Cigar <julien@perdition.city> wrote: > > >=20 > > > As I said in a previous post I tested the zfs send/receive approach (= with > > > zrep) and it works (more or less) perfectly.. so I concur in all what= you > > > said, especially about off-site replicate and synchronous replication. > > >=20 > > > Out of curiosity I'm also testing a ZFS + iSCSI + CARP at the moment,= =20 > > > I'm in the early tests, haven't done any heavy writes yet, but ATM it= =20 > > > works as expected, I havent' managed to corrupt the zpool. > >=20 > > I must be too old school, but I don=E2=80=99t quite like the idea of us= ing an essentially unreliable transport > > (Ethernet) for low-level filesystem operations. > >=20 > > In case something went wrong, that approach could risk corrupting a poo= l. Although, frankly, Now I'm thinking of the following scenario: - filer1 is the MASTER, filer2 the BACKUP - on filer1 a zpool data mirror over loc1, loc2, rem1, rem2 (where rem1=20 and rem2 are iSCSI disks) - the pool is mounted on MASTER Now imagine that the replication interface corrupts packets silently, but data are still written on rem1 and rem2. Does ZFS will detect=20 immediately that written blocks on rem1 and rem2 are corrupted? >=20 > Yeah.. although you could have silent data corruption with any broken > hardware too. Some years ago I suffered a silent data corruption due to= =20 > a broken RAID card, and had to restore from backups.. >=20 > > ZFS is extremely resilient. One of mine even survived a SAS HBA problem= that caused some > > silent corruption. >=20 > Yep, and I would certainly not use another FS to do that. Scrubbing the > pool more regularly is also something to do. >=20 > >=20 > > The advantage of ZFS send/receive of datasets is, however, that you can= consider it > > essentially atomic. A transport corruption should not cause trouble (ap= art from a failed > > "zfs receive") and with snapshot retention you can even roll back. You = can=E2=80=99t roll back > > zpool replications :) > >=20 > > ZFS receive does a lot of sanity checks as well. As long as your zfs re= ceive doesn=E2=80=99t involve a rollback > > to the latest snapshot, it won=E2=80=99t destroy anything by mistake. J= ust make sure that your replica datasets > > aren=E2=80=99t mounted and zfs receive won=E2=80=99t complain. > >=20 > >=20 > > Cheers, > >=20 > >=20 > >=20 > >=20 > > Borja. > >=20 > >=20 > >=20 >=20 > --=20 > Julien Cigar > Belgian Biodiversity Platform (http://www.biodiversity.be) > PGP fingerprint: EEF9 F697 4B68 D275 7B11 6A25 B2BB 3710 A204 23C0 > No trees were killed in the creation of this message. > However, many electrons were terribly inconvenienced. --=20 Julien Cigar Belgian Biodiversity Platform (http://www.biodiversity.be) PGP fingerprint: EEF9 F697 4B68 D275 7B11 6A25 B2BB 3710 A204 23C0 No trees were killed in the creation of this message. However, many electrons were terribly inconvenienced. --yAzUYvkKIfeS0jQX Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAABCgAGBQJXrFtIAAoJELK7NxCiBCPAc60QAJc0Trdq5aR2+B56Nru38wDs w7EsfdJtaPYqVHfn3JtinY0ShblNyvCqTWC5Cbm3yW9sJjmKht+Q1AlOuaSQM39U GVhq7SP71tnh72tgLu7UFHoagLeyF/QadJcvyYKdIJRlYMjZv5lUMdWdid2hhncb fBGGnSdyyuh+7IrGnExpG71gwv56BBDM0012831ypqSxUf++h3OQwutytjYKx1OK NEmpHgh9erTMk/wd6fb0oRKNLIK3RGiRPQijWGvkzkuURCSLcSDXCQTdNn0UQVWr I2SLaNg8HRWnEx9Ch030p7qhtjCv9jBQIyU9Vcj16ePJmqgbVXcaHHmUnH9v8sXB bO64Wgrp++ofKsqBM6dGdbqTOQGv4uJLY25uyVK+CAGUEMzvxeWhkC4A/Kubh2Dq CqfaEVhQwfPKpP3iilXZow05sFLVprqBqP8nHHUSo+QacNyuTv8ZhCaQwZSXzuL8 GVzNvt2foZndzGJCCfd0L+LhFydaJjMpnz05BQSRxVpljLrI7QSL8Jm3xTM7a9GS T1VP4dFqHHYqWEo/cGNQUPYhVYiqUIVIVwlyrZCMMaInDqIgdZQZiGdV2pn1qXJN U75nBSsKCq7wjYg7pBf2JtzP6cYZkbSgFyimK9+vH/iLNhdfnZioNEsNreggzr5Y kAesIncY5bdr1ELwLia5 =ViF3 -----END PGP SIGNATURE----- --yAzUYvkKIfeS0jQX--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20160811110235.GN70364>