From owner-freebsd-fs@FreeBSD.ORG Mon Jun 7 17:16:19 2010 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A34B61065676 for ; Mon, 7 Jun 2010 17:16:19 +0000 (UTC) (envelope-from bfriesen@simple.dallas.tx.us) Received: from blade.simplesystems.org (blade.simplesystems.org [65.66.246.74]) by mx1.freebsd.org (Postfix) with ESMTP id 668AA8FC17 for ; Mon, 7 Jun 2010 17:16:19 +0000 (UTC) Received: from freddy.simplesystems.org (freddy.simplesystems.org [65.66.246.65]) by blade.simplesystems.org (8.13.8+Sun/8.13.8) with ESMTP id o57HGISp023377; Mon, 7 Jun 2010 12:16:18 -0500 (CDT) Date: Mon, 7 Jun 2010 12:16:18 -0500 (CDT) From: Bob Friesenhahn X-X-Sender: bfriesen@freddy.simplesystems.org To: Martin Simmons In-Reply-To: <201006071655.o57GtSBg029967@higson.cam.lispworks.com> Message-ID: References: <4C0CAABA.2010506@icyb.net.ua> <20100607083428.GA48419@icarus.home.lan> <4C0CB3FC.8070001@icyb.net.ua> <20100607090850.GA49166@icarus.home.lan> <201006071112.o57BCGMf027496@higson.cam.lispworks.com> <20100607121954.GA52932@icarus.home.lan> <201006071655.o57GtSBg029967@higson.cam.lispworks.com> User-Agent: Alpine 2.01 (GSO 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.2 (blade.simplesystems.org [65.66.246.90]); Mon, 07 Jun 2010 12:16:18 -0500 (CDT) Cc: freebsd-fs@freebsd.org Subject: Re: zfs i/o error, no driver error X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 07 Jun 2010 17:16:19 -0000 On Mon, 7 Jun 2010, Martin Simmons wrote: > > It doesn't conflict if you agree that freshly written data is more likely to > be readable that data written long ago (with some curve in between). Depending on the actual failure mechanism, the inverse may actually be true. Freshly written data may be trash while old data still reads fine. > I don't know if there is any science behind that theory... The science is continually changing. A study done even 5 or 7 years ago may no longer be relevant. Regardless, actual results seen in the field count more than any theory. Bob -- Bob Friesenhahn bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/