From owner-freebsd-hackers@FreeBSD.ORG Mon Sep 8 07:40:21 2003 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 3CA7B16A4BF for ; Mon, 8 Sep 2003 07:40:21 -0700 (PDT) Received: from sizone.org (mortar.sizone.org [65.126.154.242]) by mx1.FreeBSD.org (Postfix) with ESMTP id E980943FE5 for ; Mon, 8 Sep 2003 07:40:19 -0700 (PDT) (envelope-from dgilbert@daveg.ca) Received: by sizone.org (Postfix, from userid 66) id 495082FFB2; Mon, 8 Sep 2003 10:40:19 -0400 (EDT) Received: by canoe.dclg.ca (Postfix, from userid 101) id 00E271D1CE2; Mon, 8 Sep 2003 07:16:06 -0400 (EDT) From: David Gilbert MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <16220.25846.816256.449580@canoe.dclg.ca> Date: Mon, 8 Sep 2003 07:16:06 -0400 To: freebsd-hackers@freebsd.org X-Mailer: VM 7.14 under 21.4 (patch 12) "Portable Code" XEmacs Lucid Subject: Technical Snapshot questions X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 08 Sep 2003 14:40:21 -0000 I've been using snapshots as the lowest level of my backup system on my laptop for awhile. I'm pretty sure that it's caused a little extra instability ... but I don't have hard evidence yet... it could just be normal -CURRENT churn... but that's not my question. If I have a large number of sparse files ... and I take a snapshot ... and then I fill in a previously unfilled block in the sparse file, do I have now two completely separate sparse files ... one in the snapshot and one in the filesystem proper ... or does the added block just merge itself in. If it's the latter, how much overhead would this cause? The sparse files are about 1G in size with most degrees of fullness being represented. That question brought to mind another: Does the inode of either the "real" file or the snapshot version of the file change? Or is the inode space of the snapshot separate from the filesystem proper? Dave. -- ============================================================================ |David Gilbert, Independent Contractor. | Two things can only be | |Mail: dave@daveg.ca | equal if and only if they | |http://daveg.ca | are precisely opposite. | =========================================================GLO================