From owner-freebsd-fs@FreeBSD.ORG Sat Apr 21 01:07:47 2007 Return-Path: X-Original-To: freebsd-fs@freebsd.org Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id A8D1E16A401 for ; Sat, 21 Apr 2007 01:07:47 +0000 (UTC) (envelope-from ticso@cicely12.cicely.de) Received: from raven.bwct.de (raven.bwct.de [85.159.14.73]) by mx1.freebsd.org (Postfix) with ESMTP id 1FCE613C45B for ; Sat, 21 Apr 2007 01:07:46 +0000 (UTC) (envelope-from ticso@cicely12.cicely.de) Received: from cicely5.cicely.de ([10.1.1.7]) by raven.bwct.de (8.13.4/8.13.4) with ESMTP id l3L17i49020861; Sat, 21 Apr 2007 03:07:44 +0200 (CEST) (envelope-from ticso@cicely12.cicely.de) Received: from cicely12.cicely.de (cicely12.cicely.de [10.1.1.14]) by cicely5.cicely.de (8.13.4/8.13.4) with ESMTP id l3L17ZCL015452 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Sat, 21 Apr 2007 03:07:36 +0200 (CEST) (envelope-from ticso@cicely12.cicely.de) Received: from cicely12.cicely.de (localhost [127.0.0.1]) by cicely12.cicely.de (8.13.4/8.13.3) with ESMTP id l3L17ZtF064938; Sat, 21 Apr 2007 03:07:35 +0200 (CEST) (envelope-from ticso@cicely12.cicely.de) Received: (from ticso@localhost) by cicely12.cicely.de (8.13.4/8.13.3/Submit) id l3L17ZfN064937; Sat, 21 Apr 2007 03:07:35 +0200 (CEST) (envelope-from ticso) Date: Sat, 21 Apr 2007 03:07:35 +0200 From: Bernd Walter To: Mike Wolman Message-ID: <20070421010734.GD64413@cicely12.cicely.de> References: <20070420232209.G4559@nux.eros.office> <20070421000029.N4559@nux.eros.office> <20070421000805.GA64413@cicely12.cicely.de> <20070421011716.B4559@nux.eros.office> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070421011716.B4559@nux.eros.office> X-Operating-System: FreeBSD cicely12.cicely.de 5.4-STABLE alpha User-Agent: Mutt/1.5.9i X-Spam-Status: No, score=-4.4 required=5.0 tests=ALL_TRUSTED=-1.8, BAYES_00=-2.599 autolearn=ham version=3.1.7 X-Spam-Checker-Version: SpamAssassin 3.1.7 (2006-10-05) on cicely12.cicely.de Cc: freebsd-fs@freebsd.org, ticso@cicely.de Subject: Re: lazy mirror / live backup X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: ticso@cicely.de List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 21 Apr 2007 01:07:47 -0000 On Sat, Apr 21, 2007 at 01:38:31AM +0100, Mike Wolman wrote: > My only concern is zfs is quite heavy weight (memory wise) compared to > gmirror and ufs for a simple laptop/desktop setup which you may just want > to replicate the entire drive and grab the ggatec device and be ready to > run should anything happen to the machine. Yes - that's unfortunately true. > Im sure there are other situations where running zfs on the available > hardware is not an option compared to gmirror - im not sure what the > recommended amount for freebsd but as far as i can rember the suggested > about for solaris is 1Gb - comparing to gmirror i think i have run it on a > machine doing simple home fileserving with 128Mb. Ever thought about UFS snapshots backed with rsync? You get a consitent pseudo image of your running filesystem with unallocated blocks represented as zeros. rsync now allows comparing file chunks and copies only differences. Still every block need to be read, though. vbackup from devel/plan9port stores checksums and allows offering only different blocks to the other side. venti - the backing store behind vbackup - allows compression and single storage of different blocks with same data, which reduces the required backup capacity very impressive. My expirience with vbackup is that this mechanism is fast enough as long as there are no hughe differences. -- B.Walter http://www.bwct.de http://www.fizon.de bernd@bwct.de info@bwct.de support@fizon.de