From owner-freebsd-stable@FreeBSD.ORG Mon Oct 20 17:57:26 2008 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 1C8901065672 for ; Mon, 20 Oct 2008 17:57:26 +0000 (UTC) (envelope-from zbeeble@gmail.com) Received: from yx-out-2324.google.com (yx-out-2324.google.com [74.125.44.28]) by mx1.freebsd.org (Postfix) with ESMTP id C0BB98FC14 for ; Mon, 20 Oct 2008 17:57:25 +0000 (UTC) (envelope-from zbeeble@gmail.com) Received: by yx-out-2324.google.com with SMTP id 8so338063yxb.13 for ; Mon, 20 Oct 2008 10:57:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type:references; bh=giJfsKk5Qugz6UiRpMpKVGDjDtKFvkt52qBdh7vNlH4=; b=fgV7I7x0F/RjjeQT0WaFMLu49dEbCH0ewUGqtLlvb6qE1DZlWNiNOsdwCHA3pQ/DTI A3A9Bv+Heea2Z0SMBrTcCkLBXUOJmzT6+a2afD2FeTXNYfdpZErpwS+P+XrQ/5jhCjwj B0TwUgbWTDBE1v7YNL4tqXjabpYuJ64kAF+9w= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:references; b=XkMEOC8I/kQhzrd/TZD7fw10WL0qYO2NtzJugSvFZg8C9JPBP0t1ZMdUDSkueuXzs+ 1dkmBucUO7qSdW1TcaNK6Sy4zcwHCCrqf9SfuGtzEpDMYRWPPUyGn5RoSxc+H6vsxgUG p29PcAsqAK70H1j0SOxCeLGCl5Q0jZQmOuy8A= Received: by 10.150.201.13 with SMTP id y13mr12637384ybf.113.1224525444792; Mon, 20 Oct 2008 10:57:24 -0700 (PDT) Received: by 10.150.137.11 with HTTP; Mon, 20 Oct 2008 10:57:24 -0700 (PDT) Message-ID: <5f67a8c40810201057x7bc9353dpebcea7c5abe7d30@mail.gmail.com> Date: Mon, 20 Oct 2008 13:57:24 -0400 From: "Zaphod Beeblebrox" To: "Jeremy Chadwick" In-Reply-To: <20081020173221.GA8889@icarus.home.lan> MIME-Version: 1.0 References: <200810171530.45570.joao@matik.com.br> <20081020164831.GA8016@icarus.home.lan> <45836B9A-CB6E-4B95-911E-0023230B8F82@mac.com> <200810201518.01678.joao@matik.com.br> <20081020173221.GA8889@icarus.home.lan> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: freebsd-stable@freebsd.org, JoaoBR Subject: Re: constant zfs data corruption X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 20 Oct 2008 17:57:26 -0000 On Mon, Oct 20, 2008 at 1:32 PM, Jeremy Chadwick wrote: > On Mon, Oct 20, 2008 at 03:18:01PM -0200, JoaoBR wrote: > > On Monday 20 October 2008 15:03:14 Chuck Swiger wrote: > > > On Oct 20, 2008, at 9:48 AM, Jeremy Chadwick wrote: > > > > Hm... I thought we determined earlier in this thread that the OP is > > > > not > > > > getting the benefits of ZFS checksums because he's not using raidz > > > > (only > > > > a single disk with a single pool)? > > > > > > He's not getting working filesystem redundancy with the existing > > > config and is vulnerable to losing data from a single drive failure, > > > agreed. But the ZFS checksum mechanism should still be working to > > > detect data corruption, even though ZFS cannot recover the corrupted > > > data the way it otherwise would if redundancy was available. > > > > > > > all right and understood but shouldn't something as fsck should correct > the > > error? > > No. You're using ZFS, not UFS. fsck will not work. > > In the case of underlying data corruption on ZFS, there is no way to fix > it unless you have mirroring or raidz in use. > Assuming the whole disk isn't bad and without knowing where (how far away) ZFS puts things when you do this, setting "copies=2" or "copies=3" on a non-redundant disk/pool/filesystem will allow ZFS to recover data if one of the copies is still good.