From owner-freebsd-questions@FreeBSD.ORG Fri Aug 19 14:14:04 2005 Return-Path: X-Original-To: questions@freebsd.org Delivered-To: freebsd-questions@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 1089B16A41F for ; Fri, 19 Aug 2005 14:14:04 +0000 (GMT) (envelope-from ilari.laitinen@iki.fi) Received: from fep30-app.kolumbus.fi (fep30-0.kolumbus.fi [193.229.0.32]) by mx1.FreeBSD.org (Postfix) with ESMTP id 45E1843D45 for ; Fri, 19 Aug 2005 14:14:02 +0000 (GMT) (envelope-from ilari.laitinen@iki.fi) Received: from lohi.local ([81.197.36.254]) by fep30-app.kolumbus.fi with SMTP id <20050819141401.LBJD24786.fep30-app.kolumbus.fi@lohi.local> for ; Fri, 19 Aug 2005 17:14:01 +0300 Received: by lohi.local (sSMTP sendmail emulation); Fri, 19 Aug 2005 17:15:35 +0300 Date: Fri, 19 Aug 2005 17:15:35 +0300 From: Ilari Laitinen To: questions@freebsd.org Message-ID: <20050819141535.GA62513@lohi.local> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="huq684BweRXVnRxX" Content-Disposition: inline User-Agent: Mutt/1.4.2.1i X-PGP-Key: http://iki.fi/ilari.laitinen/pubkey.asc Cc: Subject: dump(8), incremental backups, Tower of Hanoi sequence, don't get it 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: Fri, 19 Aug 2005 14:14:04 -0000 --huq684BweRXVnRxX Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hello. Lately I have been getting more and more worried about data on my FreeBSD box at home. I am forming a "real" small-scale backup policy with two different big USB harddrives (yet to buy) storing regular incremental backups (yet to figure out). The idea is to have those harddrives mirror each other for extra security. Handbook reads dump(8) is the best backup program there is. So I am giving it a try - only to find out that I don't understand at all the meaning of that modified Tower of Hanoi algorithm descibed in the manual page and elsewhere. The manual page says it is "an efficient method of staggering incremental dumps to minimize the number of tapes." I just don't get the picture here. So, could somebody please give an idiot-proof explanation why "3 2 5 4 7 6 9 8 9 9" is such a tape-number-minimizing dump level sequence (with helpful examples, if at all possible)? How does it work? Am I relatively safe doing level 0 dump every two months and increasing dump level for weekly backups like the following, given two separate harddrives storing them? Date Dump level 2005-09-01 0 2005-09-08 1 2005-09-15 2 =2E.. 2005-10-27 8 2005-11-03 0 Thanks. Ilari Laitinen, dumb dump newbie lost in this big world of ever-so-failing disks --=20 Ilari Laitinen - ilari.laitinen@iki.fi - http://iki.fi/ilari.laitinen/ --huq684BweRXVnRxX Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (FreeBSD) iD8DBQFDBemHQj4nNFSfK+YRAjX0AKCf/Ut/gyvfvKXEUkH69Q0jSV5yQwCfYqOT d5wx5asYHJqZju/cA2pnrJc= =lGaX -----END PGP SIGNATURE----- --huq684BweRXVnRxX--