From owner-freebsd-stable@FreeBSD.ORG Wed Oct 27 12:05:17 2004 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 6A80F16A4CE for ; Wed, 27 Oct 2004 12:05:17 +0000 (GMT) Received: from pi.codefab.com (pi.codefab.com [199.103.21.227]) by mx1.FreeBSD.org (Postfix) with ESMTP id 17D4443D3F for ; Wed, 27 Oct 2004 12:05:17 +0000 (GMT) (envelope-from cswiger@mac.com) Received: from [192.168.1.3] (pool-68-160-246-51.ny325.east.verizon.net [68.160.246.51]) by pi.codefab.com (8.12.11/8.12.11) with ESMTP id i9RC5Ap8086460 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 27 Oct 2004 08:05:12 -0400 (EDT) Message-ID: <417F8EF6.9060304@mac.com> Date: Wed, 27 Oct 2004 08:05:10 -0400 From: Chuck Swiger Organization: The Courts of Chaos User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.3) Gecko/20040910 X-Accept-Language: en-us, en MIME-Version: 1.0 To: miha@ghuug.org References: <200410270027.47092.miha@ghuug.org> <1098855222.15580.81.camel@emperor> <200410271114.36794.miha@ghuug.org> In-Reply-To: <200410271114.36794.miha@ghuug.org> X-Enigmail-Version: 0.86.1.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, hits=-3.3 required=5.5 tests=AWL,BAYES_00 autolearn=ham version=2.64 X-Spam-Checker-Version: SpamAssassin 2.64 (2004-01-11) on pi.codefab.com cc: freebsd-stable@freebsd.org Subject: Re: question on vinum X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 27 Oct 2004 12:05:17 -0000 Mikhail P. wrote: > On Wednesday 27 October 2004 05:33, secmgr wrote: [ ... ] >> If you want to do that, then you want raid5. If either a concat or >> stripe set looses a drive, the data will need to be restored. > > Are there known methods/techniques to restore data from failed concat or > stripe volumes? Certainly. It's known as "taking a backup", perhaps to a tape drive or some other form of storage. If you don't have a backup, and you lose a disk in a RAID-0 config, you will effectively lose all of the data. [ ... ] > Does striping require an additional drive too? No. > Or it is very similar to > concat, except for it stores data across all the spindles? Yes, that's right. > Does it also mean that it is harder to recover stripped volume? The question isn't well-phrased: you can't recover data from either if you lose a drive. > As for raid5 - it requires an additional drive. Are there any requirements for > the drive? E.g. would it work as having 3 x 200GB for stripe + additional > 20GB drive that will be used for control blocks? No. All of the drives need to be the same size. With RAID-5, which drive is used to hold parity data rotates on a stripe-by-stripe basis to balance out the load. > And what happens here if > 20GB drive fails - will I be able to rebuild it and continue using raid? You can rebuild a RAID-5 volume if a single drive fails without losing data. -- -Chuck