From owner-freebsd-questions@FreeBSD.ORG Thu Aug 23 04:03:18 2007 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 D30B416A417 for ; Thu, 23 Aug 2007 04:03:18 +0000 (UTC) (envelope-from rakhesh@rakhesh.com) Received: from nf-out-0910.google.com (nf-out-0910.google.com [64.233.182.188]) by mx1.freebsd.org (Postfix) with ESMTP id 6EF5413C458 for ; Thu, 23 Aug 2007 04:03:18 +0000 (UTC) (envelope-from rakhesh@rakhesh.com) Received: by nf-out-0910.google.com with SMTP id b2so331330nfb for ; Wed, 22 Aug 2007 21:03:17 -0700 (PDT) Received: by 10.78.147.6 with SMTP id u6mr891393hud.1187841795922; Wed, 22 Aug 2007 21:03:15 -0700 (PDT) Received: from smtp.home.rakhesh.com ( [82.178.138.167]) by mx.google.com with ESMTPS id 24sm428868huf.2007.08.22.21.03.13 (version=TLSv1/SSLv3 cipher=OTHER); Wed, 22 Aug 2007 21:03:14 -0700 (PDT) Received: from obelix.home.rakhesh.com (obelix.home.rakhesh.com [192.168.17.13]) by smtp.home.rakhesh.com (Postfix) with ESMTP id 4C49A11435; Thu, 23 Aug 2007 08:01:27 +0400 (GST) Date: Thu, 23 Aug 2007 08:01:27 +0400 (GST) X-X-Sender: rakhesh@obelix.home.rakhesh.com To: Michel Talon In-Reply-To: <20070822083729.GA93337@lpthe.jussieu.fr> Message-ID: <20070823080035.O50542@obelix.home.rakhesh.com> References: <20070822083729.GA93337@lpthe.jussieu.fr> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed From: Rakhesh Sasidharan Cc: freebsd-questions@freebsd.org Subject: Re: GEOM, Vinum difference 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: Thu, 23 Aug 2007 04:03:18 -0000 Michel Talon wrote: > Rakhesh Sasidharan wrote: > >> Another (related) question: both gvinum and the geom utilities like >> gmirror and gstripe etc provide for RAID0, RAID1, and RAID3. Any >> advantages/ disadvantages of using one instead of the other? > > There has been a polemic between Greg Lehey and PJ Dawidek about the > comparative advantages of raid3 and raid5. You can find the exchanges on > Google. One example being: > http://arkiv.freebsd.se/?ml=freebsd-performance&a=2004-08&t=227183 > As far as i remember there are arguments showing that raid3 is better > than raid5 both in terms of speed and of data security. It seems that > raid5 has mostly a hype factor for him, but i may err. Anyways it is for > such reasons that in the modern geom system, raid3 has been implemented > and not raid5. But vinum has been ported to the geom framework for the > benefit of old users, or of people who like it. For example if you are > using FreeBSD-4 or DragonFlyBSD, vinum is the standard tool, and you > may prefer getting expertise in just one tool. > > Finally none of these raid systems is really good, both for performance > and security. If you are concerned with your data and want good write > speed, you must buy enough disks and use raid 10. Another important > factor is ease of use. The geom tools, gmirror, gstripe, graid3, etc. > are *very* easy to use. The documentation in the man pages is clear, > sufficient for doing work, and not too long. On the contrary, vinum was > traditionaly documented in a very hermetic way. But more recently, Greg > Lehey has provided a very clear chapter of his book on his web site > which can be recommanded, but is not short. Note the documentation is a > critical aspect of such systems because its lack may bite you in case a > disk crashes and you need to adopt correct procedures under stress. > Also for some time the gvinum stuff was extremely buggy, and was > completely non functional when i tried it. I hope it is fixed now. Great, thanks Michael! :) That's just the sort of info I was looking for ... Regards, - Rakhesh http://rakhesh.com/