From owner-freebsd-current@FreeBSD.ORG Sat May 10 07:41:34 2003 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9FFE937B401; Sat, 10 May 2003 07:41:34 -0700 (PDT) Received: from bremen.shuttle.de (bremen.shuttle.de [194.95.249.251]) by mx1.FreeBSD.org (Postfix) with ESMTP id B1B1743FE0; Sat, 10 May 2003 07:41:33 -0700 (PDT) (envelope-from schweikh@schweikhardt.net) Received: from bremen.shuttle.de (localhost [127.0.0.1]) by bremen.shuttle.de (Postfix) with ESMTP id 0F10A17D44; Sat, 10 May 2003 16:41:32 +0200 (CEST) Received: (from uucp@localhost)h4AEfVC7011365; Sat, 10 May 2003 16:41:31 +0200 Received: (from schweikh@localhost) by hal9000.schweikhardt.net (8.12.9/8.12.9) id h4AEfW1C004768; Sat, 10 May 2003 16:41:32 +0200 (CEST) (envelope-from schweikh) Date: Sat, 10 May 2003 16:41:32 +0200 From: Jens Schweikhardt To: Farid Hajji Message-ID: <20030510144132.GA4214@schweikhardt.net> References: <200305100055.37190.me@farid-hajji.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200305100055.37190.me@farid-hajji.de> User-Agent: Mutt/1.4.1i cc: freebsd-fs@freebsd.org cc: freebsd-current@freebsd.org Subject: Re: Are snapshots always consistent? X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list Reply-To: freebsd-fs@freebsd.org List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 10 May 2003 14:41:35 -0000 Farid, On Sat, May 10, 2003 at 12:55:37AM +0200, Farid Hajji wrote: # I'm somewhat confused about snapshots. # # Are snapshots (e.g. created with dump -L) supposed to # be always in a consistent state? # # What happens if a snapshot is taken, while background # fsck is fixing a filesystem? I'm no expert in file systems, but AFAIK the bg fsck mostly looks for unreferenced blocks and puts them in the free block bitmap again, while dump reads files (contents) and does not store block bitmaps and other fs meta information. So, these operations should not interfere with one another. # If snapshots are not always consistent, how can one # be sure about dump -L output? Is it better to take # a snapshot first, fsck it, and _then_ dump the # snapshot without -L (how?)? The most appropriate place to ask this is probably freebsd-fs@ (in Cc: and Reply-To:). Regards, Jens -- Jens Schweikhardt http://www.schweikhardt.net/ SIGSIG -- signature too long (core dumped)