From owner-freebsd-fs@freebsd.org Thu Aug 11 11:19:25 2016 Return-Path: Delivered-To: freebsd-fs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 2E231BB59DE for ; Thu, 11 Aug 2016 11:19:25 +0000 (UTC) (envelope-from julien@perdition.city) Received: from relay-b01.edpnet.be (relay-b01.edpnet.be [212.71.1.221]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "edpnet.email", Issuer "Go Daddy Secure Certificate Authority - G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id D36F41720 for ; Thu, 11 Aug 2016 11:19:24 +0000 (UTC) (envelope-from julien@perdition.city) X-ASG-Debug-ID: 1470913355-0a7ff529ab1b6eba0001-3nHGF7 Received: from mordor.lan (213.211.139.72.dyn.edpnet.net [213.211.139.72]) by relay-b01.edpnet.be with ESMTP id ae7ZsecfcVglKeSC (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Thu, 11 Aug 2016 13:02:37 +0200 (CEST) X-Barracuda-Envelope-From: julien@perdition.city X-Barracuda-Effective-Source-IP: 213.211.139.72.dyn.edpnet.net[213.211.139.72] X-Barracuda-Apparent-Source-IP: 213.211.139.72 Date: Thu, 11 Aug 2016 13:02:35 +0200 From: Julien Cigar To: Borja Marcos Cc: freebsd-fs@freebsd.org, Jordan Hubbard Subject: Re: HAST + ZFS + NFS + CARP Message-ID: <20160811110235.GN70364@mordor.lan> X-ASG-Orig-Subj: Re: HAST + ZFS + NFS + CARP References: <65906F84-CFFC-40E9-8236-56AFB6BE2DE1@ixsystems.com> <61283600-A41A-4A8A-92F9-7FAFF54DD175@ixsystems.com> <20160704183643.GI41276@mordor.lan> <20160704193131.GJ41276@mordor.lan> <20160811091016.GI70364@mordor.lan> <1AA52221-9B04-4CF6-97A3-D2C2B330B7F9@sarenet.es> <20160811101539.GM70364@mordor.lan> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="yAzUYvkKIfeS0jQX" Content-Disposition: inline In-Reply-To: <20160811101539.GM70364@mordor.lan> User-Agent: Mutt/1.6.1 (2016-04-27) X-Barracuda-Connect: 213.211.139.72.dyn.edpnet.net[213.211.139.72] X-Barracuda-Start-Time: 1470913355 X-Barracuda-Encrypted: ECDHE-RSA-AES256-GCM-SHA384 X-Barracuda-URL: https://212.71.1.221:443/cgi-mod/mark.cgi X-Barracuda-Scan-Msg-Size: 3070 X-Virus-Scanned: by bsmtpd at edpnet.be X-Barracuda-BRTS-Status: 1 X-Barracuda-Bayes: INNOCENT GLOBAL 0.5000 1.0000 0.0100 X-Barracuda-Spam-Score: 0.01 X-Barracuda-Spam-Status: No, SCORE=0.01 using global scores of TAG_LEVEL=1000.0 QUARANTINE_LEVEL=1000.0 KILL_LEVEL=6.0 tests= X-Barracuda-Spam-Report: Code version 3.2, rules version 3.2.3.31929 Rule breakdown below pts rule name description ---- ---------------------- -------------------------------------------------- X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 11 Aug 2016 11:19:25 -0000 --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 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. 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