From owner-freebsd-questions@FreeBSD.ORG Sat Apr 7 09:35:58 2007 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 7740D16A405 for ; Sat, 7 Apr 2007 09:35:58 +0000 (UTC) (envelope-from mike@nux.co.uk) Received: from smtp.nildram.co.uk (smtp.nildram.co.uk [195.112.4.54]) by mx1.freebsd.org (Postfix) with ESMTP id 3E0B113C45D for ; Sat, 7 Apr 2007 09:35:58 +0000 (UTC) (envelope-from mike@nux.co.uk) Received: from office.nux.co.uk (unknown [82.133.40.67]) by smtp.nildram.co.uk (Postfix) with ESMTP id F149C2B7C12 for ; Sat, 7 Apr 2007 10:35:54 +0100 (BST) Received: (qmail 20780 invoked by uid 2223); 7 Apr 2007 09:35:56 -0000 Received: from localhost (sendmail-bs@127.0.0.1) by localhost with SMTP; 7 Apr 2007 09:35:56 -0000 Date: Sat, 7 Apr 2007 10:35:56 +0100 (BST) From: Mike Wolman X-X-Sender: mike@nux.eros.office To: "R. B. Riddick" In-Reply-To: <219395.34786.qm@web30302.mail.mud.yahoo.com> Message-ID: <20070407103057.P20396@nux.eros.office> References: <219395.34786.qm@web30302.mail.mud.yahoo.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: freebsd-fs@FreeBSD.org, freebsd-questions@freebsd.org Subject: Re: some thoughts about gmirror 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: Sat, 07 Apr 2007 09:35:58 -0000 Rsync is a great tool however if you try to rsync a filesystem with hundreds of thousand files in it the file list can use quite a large amount of bandwidth even if only a single file has changed - if you were keeping track of the blocks which had changed then you do not need to generate this list and simply send over the changed blocks. I was not thinking the remote side would mount the image unless the primary site was offline/unavailable. Mike. On Fri, 6 Apr 2007, R. B. Riddick wrote: > --- Mike Wolman wrote: >> It could also be used for asynchronous mirrors over slow links, if the log >> device was always written to first then the write latency for long distant >> links could be removed. Im not sure if it would be possible to achieve >> this using just a modified ggatec instead which has a local device used >> as a write cache. >> > Sounds like rsync can already do that (I am not sure right now, if rsync can > find updated areas within a large file, or if it just copies the while updated > file even if it is a large one)... > > Furthermore the remote consumer of that gmirror couldnt be mounted RW, if it > uses UFS, because UFS doesnt allow multiple RW mounts at the same time... > > -Arne > > > > ____________________________________________________________________________________ > Food fight? Enjoy some healthy debate > in the Yahoo! Answers Food & Drink Q&A. > http://answers.yahoo.com/dir/?link=list&sid=396545367 > >