From owner-freebsd-hackers@FreeBSD.ORG Mon Jun 1 08:32:16 2009 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 703DF1065675 for ; Mon, 1 Jun 2009 08:32:16 +0000 (UTC) (envelope-from kraduk@googlemail.com) Received: from mail-ew0-f212.google.com (mail-ew0-f212.google.com [209.85.219.212]) by mx1.freebsd.org (Postfix) with ESMTP id C99D68FC1E for ; Mon, 1 Jun 2009 08:32:10 +0000 (UTC) (envelope-from kraduk@googlemail.com) Received: by ewy8 with SMTP id 8so4183798ewy.43 for ; Mon, 01 Jun 2009 01:32:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=domainkey-signature:received:received:from:to:references:subject :date:message-id:mime-version:content-type:content-transfer-encoding :x-mailer:in-reply-to:x-mimeole:thread-index; bh=LrevFt41X3lTBp00j+yIPU44tpI7yKNADmPYUeviyl0=; b=caRBgM4eLezIl2zLAM56bj6xAW01NBijFXjvkvK8+VBqwoH0lwS/IFLZq1L2K+nlmz T7eXoGEAgBoxlcfj7Gf3Vx1qoUcZnHvuaXq5r1wrWeSaN513AsgWdA5+FGVAOcl+ARF6 mfXCXrhkFl8FpCB7Y5SV4w+qYOycnVdgBUaMk= DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=from:to:references:subject:date:message-id:mime-version :content-type:content-transfer-encoding:x-mailer:in-reply-to :x-mimeole:thread-index; b=YWpXqr2WxkXTkDoBuXA0HSaVPfLkWhZOG+fZOICgqmudB2zzwtSO/gaQO+XvdOXCj0 0BKMMWo/CZMLMYyb12Rx6JSVGJL2xiHkJhtPtwiuJfHRgVowy/FCyagJTO6HNNpEFBBp 9G21/Nrc5O9verv79tCos67fGzM40Cf7s5C/I= Received: by 10.210.16.11 with SMTP id 11mr2561634ebp.87.1243845129922; Mon, 01 Jun 2009 01:32:09 -0700 (PDT) Received: from LTPCSCOTT (e1-1.ns500-1.ts.milt.as9105.net [212.74.112.53]) by mx.google.com with ESMTPS id 4sm6600778ewy.56.2009.06.01.01.32.09 (version=SSLv3 cipher=RC4-MD5); Mon, 01 Jun 2009 01:32:09 -0700 (PDT) From: krad To: , References: <20090530175239.GA25604@logik.internal.network><20090530144354.2255f722@bhuda.mired.org><20090530191840.GA68514@logik.internal.network><20090530162744.5d77e9d1@bhuda.mired.org><20090531201445.GA82420@logik.internal.network><0229B3BF1BE94C82AA11FD06CBE0BDEF@uk.tiscali.intl> <20090531235943.GA77374@logik.internal.network> Date: Mon, 1 Jun 2009 09:32:09 +0100 Message-ID: <3346D963EE2E4D28AE89CB71C2F92939@uk.tiscali.intl> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Office Outlook 11 In-Reply-To: <20090531235943.GA77374@logik.internal.network> X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 Thread-Index: AcniS+nR4L5WeuIeQ4ywxE/MVb7YzQARmMJg X-Mailman-Approved-At: Mon, 01 Jun 2009 11:24:22 +0000 Cc: Subject: RE: Request for opinions - gvinum or ccd? X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 01 Jun 2009 08:32:19 -0000 Zfs has been designed for highly scalable redundant disk pools therefore using it on a single drive kind of goes against it ethos. Remember a lot of the blurb in the man page was written by sun and therefore is written with corporates in mind, therefore the cost with of the data vs an extra drive being so large why wouldn't you make it redundant. Having said that sata drives are cheap these days so you would have to be on the tightest of budgets not to do a mirror. Having said all this we quite often us zfs on a single drive, well sort of. The sun clusters have external storage for the shared file systems. These are usually a bunch of drives, raid 5, 10 or whatever. Then export a single lun, which is presented to the various nodes. There is a zpool created on this LUN. So to all intents and purposes zfs thinks its on a single drive (the redundancy provided by the external array). This is common practice and we see no issues with it. -----Original Message----- From: owner-freebsd-hackers@freebsd.org [mailto:owner-freebsd-hackers@freebsd.org] On Behalf Of xorquewasp@googlemail.com Sent: 01 June 2009 01:00 To: freebsd-hackers@freebsd.org Subject: Re: Request for opinions - gvinum or ccd? There is one last thing I'd like clarified. From the zpool manpage: In order to take advantage of these features, a pool must make use of some form of redundancy, using either mirrored or raidz groups. While ZFS supports running in a non-redundant configuration, where each root vdev is simply a disk or file, this is strongly discouraged. A single case of bit corruption can render some or all of your data unavailable. Is this supposed to mean: "ZFS is more fragile than most. If you don't use redundancy, one case of bit corruption will destroy the filesystem" Or: "Hard disks explode often. Use redundancy." _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org"