From owner-freebsd-questions@FreeBSD.ORG Fri Nov 28 17:30:05 2008 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 9EED81065675 for ; Fri, 28 Nov 2008 17:30:05 +0000 (UTC) (envelope-from fbsd.questions@rachie.is-a-geek.net) Received: from mail.rachie.is-a-geek.net (rachie.is-a-geek.net [66.230.99.27]) by mx1.freebsd.org (Postfix) with ESMTP id 7455D8FC16 for ; Fri, 28 Nov 2008 17:30:05 +0000 (UTC) (envelope-from fbsd.questions@rachie.is-a-geek.net) Received: from localhost (mail.rachie.is-a-geek.net [192.168.2.101]) by mail.rachie.is-a-geek.net (Postfix) with ESMTP id B04CFAFCF5D; Fri, 28 Nov 2008 08:30:04 -0900 (AKST) From: Mel To: freebsd-questions@freebsd.org Date: Fri, 28 Nov 2008 18:29:55 +0100 User-Agent: KMail/1.9.7 References: <200811281008.19578.af300wsm@gmail.com> In-Reply-To: <200811281008.19578.af300wsm@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200811281829.58003.fbsd.questions@rachie.is-a-geek.net> Cc: Andrew Falanga Subject: Re: gmirror and the UFS file systems X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 28 Nov 2008 17:30:05 -0000 On Friday 28 November 2008 18:08:19 Andrew Falanga wrote: > I'm getting ready to move forward on enabling gmirror on my churches > website server (FreeBSD 7.0-RELEASE p4). I used defaults during the > install (most importantly for this, the file system defaults). I've read > in the manual pages that the data for the mirror is contained in the last > sector of the drive/partitions. So, I want to mirror the entire drive > (ad4) to the second drive (ad5). This server doesn't yet have much data at > all. I'm wondering if I turn on this mirror, will anything important be > overwritten in the last sector? I've converted UFS filesystems with just the base install and a few ports over to gmirror many times and no problem. I guess the question can best be paraphrased as: "If I cross a street in a residential area at 4am in the morning, will I get hit by a car?" Also, gmirror create will tell you if the last sector contains data, just like a driver would honk his horn. -- Mel Problem with today's modular software: they start with the modules and never get to the software part.