From owner-freebsd-questions@FreeBSD.ORG Wed Aug 6 01:19:53 2014 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 73A896CB for ; Wed, 6 Aug 2014 01:19:53 +0000 (UTC) Received: from mail-qg0-f54.google.com (mail-qg0-f54.google.com [209.85.192.54]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 2DD1E2443 for ; Wed, 6 Aug 2014 01:19:52 +0000 (UTC) Received: by mail-qg0-f54.google.com with SMTP id z60so2015139qgd.13 for ; Tue, 05 Aug 2014 18:19:44 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:content-type:mime-version:subject:from :in-reply-to:date:content-transfer-encoding:message-id:references:to; bh=Nci78v64cqedQDr71LpZr87JFTyDXBPoOQQIETxsSN8=; b=gRVN4FspqL7ZRfSAChuNp/XQ97iYpqYRlKaXqCEvBYDXHxU1JQ07Yg6Oho7IJO4Bjk RzY4PIJnnBVzsxUYGDQNGWCTXGihdEVQxZreUczu36hWGpkePNlagGy4ub+Po21TfstZ UNkR9GWYEqcLZ51few7JQp4rVQ+xN0d+TeY4s6sWQ8b9zNXGtvir8MHWxcGeqomEA948 UvRGXj4RwOphFpToXp7+DSuhQUxtAB2PE0a6zmFmJjQHhVcpkOE6ojbjPPTt0qXx+YFS c0epACcFVxfzBBGzbmiS3gldlYTO8BRrQINYvAfg35NrETz7Y2sxq426fp4lgIbumKjV gSRQ== X-Gm-Message-State: ALoCoQll6I8RtVY/rbKvI01uEHBgT1WsJ1cSLgbTdihhTpBdNNXaRzGYHEktzkKP0k3wXvFt2Lt5 X-Received: by 10.140.92.235 with SMTP id b98mr10685998qge.97.1407287984070; Tue, 05 Aug 2014 18:19:44 -0700 (PDT) Received: from [192.168.1.127] (c-71-234-255-65.hsd1.vt.comcast.net. [71.234.255.65]) by mx.google.com with ESMTPSA id p12sm3684391qga.0.2014.08.05.18.19.43 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 05 Aug 2014 18:19:43 -0700 (PDT) Content-Type: text/plain; charset=windows-1252 Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Subject: ZFS under FreeBSD failure modes From: Paul Kraus In-Reply-To: <20140802213848.GC77128@neutralgood.org> Date: Tue, 5 Aug 2014 21:19:41 -0400 Content-Transfer-Encoding: quoted-printable Message-Id: References: <53DAFCF2.2070909@hiwaay.net> <53DB9797.1010702@hiwaay.net> <20140801164335.GA16376@slackbox.erewhon.home> <53DBF71D.3080807@hiwaay.net> <20140801232843.GB17393@slackbox.erewhon.home> <53DCF32A.30700@hiwaay.net> <20140802185442.GA28910@slackbox.erewhon.home> <53DD533D.7090700@hiwaay.net> <20140802213848.GC77128@neutralgood.org> To: FreeBSD Questions !!!! X-Mailer: Apple Mail (2.1878.6) X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 06 Aug 2014 01:19:53 -0000 On Aug 2, 2014, at 17:38, kpneal@pobox.com wrote: > I'd be careful running ZFS on a machine that lacks ECC memory. Lots of > people do it, but I'd be worried that ZFS would get itself into a = state > where you couldn't access anything. I am startring to see comments like this on a more frequent basis. What = is the failure mechanism you expect to run into here? > UFS I believe handles some kinds of > damage better than ZFS. Can you please be specific. I reed asking this question in another = thread and just received snide comments back. What *specific* failure = modes, and I am looking for technical details here, does UFS handle = better than ZFS and why? What is it about ZFS that does not handle that = failure? > When was the last time anyone heard of a UFS file > system being so damaged that it couldn't be recovered? Anecdotal evidence at best. I have plenty of anecdotal evidence that ZFS = never looses data. I don=92t claim it as fact.=20 In the early years of ZFS (and in the early years of ZFS under FreeBSD) = it was much more picky about how you did things. One example; an = absolute rule of mine was to never, ever relocate drives from an = IMPORTED zpool. I had seen too many reports of zpools being corrupted or = otherwise rendered unable to be mounted when drives were moved around. = Both the ZFS code and the underlying device driver code is much better = today, so it is much less of an issue (but I still try to avoid it, I = EXPORT the pool before I make any hardware changes). -- Paul Kraus paul@kraus-haus.org