From owner-freebsd-fs@FreeBSD.ORG Sun May 11 05:55:03 2003 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id D1B6937B401 for ; Sun, 11 May 2003 05:55:03 -0700 (PDT) Received: from dsl-mail.kamp.net (mail.kamp-dsl.de [195.62.99.42]) by mx1.FreeBSD.org (Postfix) with SMTP id 0EB8143FB1 for ; Sun, 11 May 2003 05:55:02 -0700 (PDT) (envelope-from me@farid-hajji.de) Received: (qmail 5228 invoked by uid 505); 11 May 2003 12:55:03 -0000 Received: from me@farid-hajji.de by dsl-mail by uid 502 with qmail-scanner-1.14 (spamassassin: 2.43. Clear:. Processed in 0.707024 secs); 11 May 2003 12:55:03 -0000 Received: from unknown (HELO reverse-213-146-115-183.dialin.kamp-dsl.de) (213.146.115.183) by dsl-mail.kamp.net with SMTP; 11 May 2003 12:55:02 -0000 From: Farid Hajji To: freebsd-fs@freebsd.org Date: Sun, 11 May 2003 14:55:27 +0200 User-Agent: KMail/1.5.1 References: <200305100055.37190.me@farid-hajji.de> <20030510144132.GA4214@schweikhardt.net> In-Reply-To: <20030510144132.GA4214@schweikhardt.net> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200305111455.28175.me@farid-hajji.de> cc: schweikh@schweikhardt.net Subject: Re: Are snapshots always consistent? X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list Reply-To: me@farid-hajji.de List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 11 May 2003 12:55:04 -0000 Hello Jens, > # 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. dump saves the contents of inodes. This is more than just file contents and fsck operates on inodes. So there is potential for breakage if fsck is in the process of modifying inodes (e.g. block counts). > Regards, > > Jens -- Farid Hajji -- Unix Systems and Network Management. http://www.farid-hajji.net/address.html Quoth the Raven, "Nevermore." --Edgar Allan Poe.