From owner-freebsd-fs@FreeBSD.ORG Fri Apr 20 22:40:52 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 1B2E216A400 for ; Fri, 20 Apr 2007 22:40:52 +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 D9C5913C455 for ; Fri, 20 Apr 2007 22:40:51 +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 714C12B59DD for ; Fri, 20 Apr 2007 23:40:46 +0100 (BST) Received: (qmail 6389 invoked by uid 2223); 20 Apr 2007 22:40:50 -0000 Received: from localhost (sendmail-bs@127.0.0.1) by localhost with SMTP; 20 Apr 2007 22:40:50 -0000 Date: Fri, 20 Apr 2007 23:40:50 +0100 (BST) From: Mike Wolman X-X-Sender: mike@nux.eros.office To: roberto@keltia.freenix.fr, freebsd-fs@freebsd.org Message-ID: <20070420232209.G4559@nux.eros.office> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: Subject: lazy mirror / live backup X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 20 Apr 2007 22:40:52 -0000 >> I'd like the ability to have gmirror do a more efficient re-silvering (or >> re-syncing) of the mirror members when a planned disconnect occurs. This >> would significantly reduce the mirror rebuild time for any component which >> had been deactivated, for network mirrors using ggated devices this would >> also reduce network usage and could be used for remote asynced mirrors >> thus providing a live backup for laptops/workstations. >Do you see that you are describing ZFS there? Considering the status of >ZFS right now, I think it is not worth really trying to implement such >scheme in gmirror. The problem with zfs is you cannot layer it as u can with the geom classes. For example if you want to create a failover zfs storage pool, if you make the zfs pool out of gmirror devices with one being a local device and the other being a ggatec device. You would then have your zfs raidz pool replicated on a remote host. I do not think you can do this with zfs by itself as you are not able to layer raidz pool ontop of a load of zfs mirrors. Mike.