From owner-freebsd-fs@freebsd.org Wed Aug 17 08:53:27 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 4F88EBBA6EC for ; Wed, 17 Aug 2016 08:53:27 +0000 (UTC) (envelope-from borjam@sarenet.es) Received: from cu01176b.smtpx.saremail.com (cu01176b.smtpx.saremail.com [195.16.151.151]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 0D1031016 for ; Wed, 17 Aug 2016 08:53:26 +0000 (UTC) (envelope-from borjam@sarenet.es) Received: from [172.16.8.36] (izaro.sarenet.es [192.148.167.11]) by proxypop01.sare.net (Postfix) with ESMTPSA id C69B99DCA35; Wed, 17 Aug 2016 10:53:17 +0200 (CEST) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) Subject: Re: HAST + ZFS + NFS + CARP From: Borja Marcos In-Reply-To: <472bc879-977f-8c4c-c91a-84cc61efcd86@internetx.com> Date: Wed, 17 Aug 2016 10:53:17 +0200 Cc: freebsd-fs@freebsd.org Content-Transfer-Encoding: quoted-printable Message-Id: <1AE36A3B-A2BA-47D2-A872-1E7E9EFA201D@sarenet.es> References: <6035AB85-8E62-4F0A-9FA8-125B31A7A387@gmail.com> <20160703192945.GE41276@mordor.lan> <20160703214723.GF41276@mordor.lan> <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> <472bc879-977f-8c4c-c91a-84cc61efcd86@internetx.com> To: juergen.gotteswinter@internetx.com X-Mailer: Apple Mail (2.3124) 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: Wed, 17 Aug 2016 08:53:27 -0000 > On 17 Aug 2016, at 09:25, InterNetX - Juergen Gotteswinter = wrote: > try dual split import :D i mean, zpool -f import on 2 machines hooked = up > to the same disk chassis. >=20 > kaboom, really ugly kaboom. thats what is very likely to happen sooner > or later especially when it comes to homegrown automatism solutions. > even the commercial parts where much more time/work goes into such > solutions fail in a regular manner Well, don=E2=80=99t expect to father children after shooting your balls! = ;) I am not a big fan of such closely coupled solutions. There are quite some failure modes that can break such a configuration, not just a = brainless =E2=80=9Cdual split import=E2=80=9D as you say :) Misbehaving software (read, a ZFS bug) can render the pool unusable and, = no matter how many redundant servers you have connected to your chassis, you are toast. = Using incremental replication over a network is much more robust, and it offers a lot of fault = isolation. Moreover, you can place the servers in different buildings, etc. Networks even offer a more than reasonable protection from electrical = problems. Especially if you get paranoid and use fiber, in which case protection is absolute. Borja.