From owner-freebsd-questions@FreeBSD.ORG Sat Oct 17 23:22:27 2009 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 4DB3A1065670 for ; Sat, 17 Oct 2009 23:22:27 +0000 (UTC) (envelope-from jerrymc@gizmo.acns.msu.edu) Received: from gizmo.acns.msu.edu (gizmo.acns.msu.edu [35.8.1.43]) by mx1.freebsd.org (Postfix) with ESMTP id 0C8C38FC08 for ; Sat, 17 Oct 2009 23:22:26 +0000 (UTC) Received: from gizmo.acns.msu.edu (localhost [127.0.0.1]) by gizmo.acns.msu.edu (8.13.6/8.13.6) with ESMTP id n9HNLWVE066211; Sat, 17 Oct 2009 19:21:32 -0400 (EDT) (envelope-from jerrymc@gizmo.acns.msu.edu) Received: (from jerrymc@localhost) by gizmo.acns.msu.edu (8.13.6/8.13.6/Submit) id n9HNLVIf066210; Sat, 17 Oct 2009 19:21:31 -0400 (EDT) (envelope-from jerrymc) Date: Sat, 17 Oct 2009 19:21:31 -0400 From: Jerry McAllister To: Tim Judd Message-ID: <20091017232131.GB66093@gizmo.acns.msu.edu> References: <1255727601.4640.4.camel@x1-6-00-11-09-00-e4-00.search.b.superkabel.de> <20091016213732.GA61433@gizmo.acns.msu.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.2i Cc: Jerry McAllister , freebsd-questions@freebsd.org Subject: Re: small question about tape-based dumps 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, 17 Oct 2009 23:22:27 -0000 On Fri, Oct 16, 2009 at 08:43:26PM -0600, Tim Judd wrote: > Replies inline > > On 10/16/09, Jerry McAllister wrote: > > On Fri, Oct 16, 2009 at 11:13:21PM +0200, Stevan Tiefert wrote: > > > >> Hello list, > >> > >> one example: If I have three partitions and I want to backup every day > >> these partitions, will I need 21 tapes? > >> > >> I ask because it seems it is not possible to place more than one dump on > >> one tape, isn't it? > > > > You can easily put more than one dump on a tape if there is > > room enough for them. Check out the mt(1) command. > > > > Something like mt fsf 1 will skip over the first dump file > > so you can write the second. mt fsf 2 will skip over two files, etc. > > That is dump files, not files within the dump. Each dump of a > > filesystem is one file. > > > > If you need to restore, it is just the same. The first dump is > > the first file. The second dump is reached by skipping 1 file > > with the mt command, etc. > > > > I actually rewind and skip between each dump of multiples made > > to the same tape. I also use the no-rewind device for the tape. > > > > So first dump is: dump 0af /dev/nsa0 / > > I understand that this creates a dumpfile on nsa0, and as I understand > tapes (which may be wrong, which I ask for clarification here).. To > mark a end-of-file to be able to fast-forward/rewind, why can't you > use: > mt -f /dev/nsa0 weof > > It's description in mt(1) says it writes the end-of-file mark at > current position You do not need to. dump alrady writes that when it finishes each time. If you to that, you will get a second one at that location. You do not need to do the rewind and mt fsf between each dump. I just do it to make it very clear to myself in my scripts what I am expecting and that I am doing it right. ////jerry > > > For second dump: mt -f /dev/nsa0 rewind > > mt -f /dev/nsa0 fsf 1 > > dump 0af /dev/nsa0 /usr > > So if we use weof, would the 2nd dump then be: > dump 0af /dev/nsa0 /usr > mt -f /dev/nsa0 weof > > > third mt -f /dev/nsa0 rewind > > mt -f /dev/nsa0 fsf 2 > > dump 0af /dev/nsa0 /var > > And 3rd: > dump 0af /dev/nsa0 /var > mt -f /dev/nsa0 weof > > > etc. > > > > when all done mt -f /dev/nsa0 rewind > > mt -f /dev/nsa0 offline > > And I've never used offline, guess I'll start now. > > > I have this all in a script that also writes an index file > > as the first file on the tape. > > > > Of course if you are doing a change dump the dump command is > > going to look more like: > > > > dump 1af /dev/nsa0 > > etc. > > > > ////jerry > > > >> > >> With regards > >> Stevan Tiefert > > > > Thanks for any input! > --TJ