From owner-freebsd-questions@FreeBSD.ORG Sun Jun 10 23:10:45 2012 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 0E72F106566C for ; Sun, 10 Jun 2012 23:10:45 +0000 (UTC) (envelope-from feenberg@nber.org) Received: from mail2.nber.org (mail2.nber.org [66.251.72.79]) by mx1.freebsd.org (Postfix) with ESMTP id 94C8E8FC0C for ; Sun, 10 Jun 2012 23:10:44 +0000 (UTC) Received: from nber6 (nber6.nber.org [66.251.72.76]) by mail2.nber.org (8.14.4/8.14.4) with ESMTP id q5ANAZTm097457; Sun, 10 Jun 2012 19:10:36 -0400 (EDT) (envelope-from feenberg@nber.org) Date: Sun, 10 Jun 2012 19:03:59 -0400 (EDT) From: Daniel Feenberg X-X-Sender: feenberg@nber6 To: "Ronald F. Guilmette" In-Reply-To: <48302.1339366497@tristatelogic.com> Message-ID: References: <48302.1339366497@tristatelogic.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Anti-Virus: Kaspersky Anti-Virus for Linux Mail Server 5.6.39/RELEASE, bases: 20120610 #8172196, check: 20120610 clean Cc: freebsd-questions@freebsd.org Subject: Re: Making a bootable backup (hard)disk... how? 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: Sun, 10 Jun 2012 23:10:45 -0000 On Sun, 10 Jun 2012, Ronald F. Guilmette wrote: > > > What I don't understand (and what I wish someone would enlighten me about) > is just this: It would seem that in order to implement these dump levels, > dump must be keeping a record somewhere, for each file in the filesystem, > of the level at which that file was last dumped. But where is this infor- > mation stored, exactly?? I won't be able to sleep until I know. > Only the dates of the levels of backup are stored, in /etc/dumpdates. Then the fact that a file has been dumped is inferred by comparing the file's last mod date with the dates in /etc/dumpdates. See the -T and -u options of the dump man page where this is implied but perhaps not actually stated. It does occur to me that /etc is not a felicitous place to keep this information, but given the desirability of dumping filesystems in read only state, placing the dump dates in the filesystem itself isn't feasible. daniel feenberg