From owner-freebsd-stable@FreeBSD.ORG Mon Nov 22 22:14:13 2010 Return-Path: Delivered-To: stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 1F63C1065694 for ; Mon, 22 Nov 2010 22:14:13 +0000 (UTC) (envelope-from areilly@bigpond.net.au) Received: from nschwmtas02p.mx.bigpond.com (nschwmtas02p.mx.bigpond.com [61.9.189.140]) by mx1.freebsd.org (Postfix) with ESMTP id B0D178FC12 for ; Mon, 22 Nov 2010 22:14:12 +0000 (UTC) Received: from nschwotgx04p.mx.bigpond.com ([124.188.161.100]) by nschwmtas02p.mx.bigpond.com with ESMTP id <20101122221410.LGEE25233.nschwmtas02p.mx.bigpond.com@nschwotgx04p.mx.bigpond.com>; Mon, 22 Nov 2010 22:14:10 +0000 Received: from johnny.reilly.home ([124.188.161.100]) by nschwotgx04p.mx.bigpond.com with ESMTP id <20101122221410.TDJU781.nschwotgx04p.mx.bigpond.com@johnny.reilly.home>; Mon, 22 Nov 2010 22:14:10 +0000 Date: Tue, 23 Nov 2010 09:13:50 +1100 From: Andrew Reilly To: Jonathan Stewart Message-ID: <20101122221350.GA81098@johnny.reilly.home> References: <20101122113541.GA74719@johnny.reilly.home> <4CEA8BA6.7080009@kc8onw.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4CEA8BA6.7080009@kc8onw.net> User-Agent: Mutt/1.4.2.3i X-RPD-ScanID: Class unknown; VirusThreatLevel unknown, RefID str=0001.0A150204.4CEAEB32.00CA,ss=1,fgs=0 Cc: stable@freebsd.org Subject: Re: ZFS backups: retrieving a few files? X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 22 Nov 2010 22:14:13 -0000 On Mon, Nov 22, 2010 at 10:26:30AM -0500, Jonathan Stewart wrote: > On 11/22/2010 6:35 AM, Andrew Reilly wrote: > >Dump/restore doesn't work for ZFS. I *think* that I'm running > >backups in the appropriate equivalent fashion: I take file > >system snapshots (both absolute == level 0) and relative > >(incremental), and zfs send those to files on the backup disk. > > This is actively discouraged, there is no recovery ability when > receiving zfs streams so 1 bad bit would invalidate your entire backup. Hmm. Isn't that a problem that also affects the "sending snapshots" scheme that you describe, below? > The currently accepted practice is to create a ZFS file system on the > backup drive and just keep sending incremental snapshots to it. As long > as the backup drive and host system have a snapshot in common you can do > incremental transfers. This way you only have to keep the most recent > snapshot on the main system and can keep as many as you have space for > on the backup drive. You also have direct access to any backed up > version of every file. That sounds like a very cool notion. Not unlike the time-machine scheme. Interesting how different capabilities require going back and re-thinking the problem, rather than just trying to implement the old solution with the new tools. I'll see how I go with it... Cheers, -- Andrew