From owner-freebsd-stable@FreeBSD.ORG Thu Jan 5 09:56:28 2012 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 1C2D51065670 for ; Thu, 5 Jan 2012 09:56:28 +0000 (UTC) (envelope-from m.seaman@infracaninophile.co.uk) Received: from smtp.infracaninophile.co.uk (smtp6.infracaninophile.co.uk [IPv6:2001:8b0:151:1:3cd3:cd67:fafa:3d78]) by mx1.freebsd.org (Postfix) with ESMTP id 96BB68FC1B for ; Thu, 5 Jan 2012 09:56:27 +0000 (UTC) Received: from seedling.black-earth.co.uk (seedling.black-earth.co.uk [IPv6:2001:8b0:151:1:fa1e:dfff:feda:c0bb]) (authenticated bits=0) by smtp.infracaninophile.co.uk (8.14.5/8.14.5) with ESMTP id q059uAqa066151 (version=TLSv1/SSLv3 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=NO) for ; Thu, 5 Jan 2012 09:56:18 GMT (envelope-from m.seaman@infracaninophile.co.uk) X-DKIM: OpenDKIM Filter v2.4.1 smtp.infracaninophile.co.uk q059uAqa066151 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=infracaninophile.co.uk; s=201001-infracaninophile; t=1325757379; bh=n5yEjFERh/iYJuIeDS0O6U95q6SSc+cLvelNS+BRlW0=; h=Message-ID:Date:From:MIME-Version:To:Subject:References: In-Reply-To:Content-Type:Cc; b=qcoP90KuJ8Dw2QuI5mVTYdUirVdhIlHtqO+c2SSQSJj07SK1qa33w+pKGOS7sRDRr 5btjO1tKNcLiYVwkkVJ5TMDuVEPLzgeEwB8OkxKOJY6ik3kvwNKa7c+fDVFuhW8EwG UYPES3Qi/7EhxvG2ChiZne7Yrbic39XXN3AtGavE= Message-ID: <4F0573B2.9070301@infracaninophile.co.uk> Date: Thu, 05 Jan 2012 09:56:02 +0000 From: Matthew Seaman User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:9.0) Gecko/20111222 Thunderbird/9.0.1 MIME-Version: 1.0 To: freebsd-stable@freebsd.org References: <20120104194313.GA2558@lordcow.org> In-Reply-To: <20120104194313.GA2558@lordcow.org> X-Enigmail-Version: 1.3.4 OpenPGP: id=60AE908C Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enigB852D3AB7FD3DEFF31488F6E" X-Virus-Scanned: clamav-milter 0.97.3 at lucid-nonsense.infracaninophile.co.uk X-Virus-Status: Clean X-Spam-Status: No, score=-2.5 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU autolearn=ham version=3.3.2 X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on lucid-nonsense.infracaninophile.co.uk Subject: Re: gmirror not synced 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: Thu, 05 Jan 2012 09:56:28 -0000 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigB852D3AB7FD3DEFF31488F6E Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 04/01/2012 19:43, Gareth de Vaux wrote: > Hi all, I've noticed that the md5 hashes of a couple of files on > a gmirror change when I recalculate the hashes. The output usually > cycles between 2 hashes per file. >=20 > I'm guessing this is because each calculation reads the file > randomly from 1 of 2 component drives, and the files in question > had a few bit flips during their original sync. I also assume > this's something you have to live with for gmirror? Is removing > and completely rebuilding the secondary drive the only thing you > can do (which might fix these bit flips but incur others elsewhere)? No, that's not something acceptable at all. Randomly flipping bits in files is a really nasty failure mode. What does 'gmirror list' tell you about the state of the gmirror? Is there any possibility that your hardware is failing? Check the SMART attributes of the disk in the first instance (it isn't brilliant for picking up impending failure, but it should be pretty accurate once the drive is actually generating errors.) Also try a few passes of memtest86 to try and spot problems with RAM. Cleaning dust out of air vents and heatsinks and generally making sure the machine is not overheating is a good idea too. Actually, first thing to do is make sure you have really good backups. Bonus points if you have been backing everything up religiously, and can extract a known good copy of the files in question from some of the older ones. Cheers, Matthew --=20 Dr Matthew J Seaman MA, D.Phil. 7 Priory Courtyard Flat 3 PGP: http://www.infracaninophile.co.uk/pgpkey Ramsgate JID: matthew@infracaninophile.co.uk Kent, CT11 9PW --------------enigB852D3AB7FD3DEFF31488F6E Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.16 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk8Fc7kACgkQ8Mjk52CukIwYfQCaA0WkHVdj5Lfo1brWzkk3wTmN 6M8AnRlCpci5WIW6xVLOyGXlLXRAry9U =giPQ -----END PGP SIGNATURE----- --------------enigB852D3AB7FD3DEFF31488F6E--