From owner-freebsd-questions Thu Mar 25 22:53: 5 1999 Delivered-To: freebsd-questions@freebsd.org Received: from implode.root.com (root.com [209.102.106.178]) by hub.freebsd.org (Postfix) with ESMTP id 41A5514E4B for ; Thu, 25 Mar 1999 22:52:55 -0800 (PST) (envelope-from root@implode.root.com) Received: from implode.root.com (localhost [127.0.0.1]) by implode.root.com (8.8.8/8.8.5) with ESMTP id WAA00675; Thu, 25 Mar 1999 22:51:25 -0800 (PST) Message-Id: <199903260651.WAA00675@implode.root.com> To: Evgeny Roubinchtein Cc: freebsd-questions@FreeBSD.ORG Subject: Re: "dump" of a "live" file system? In-reply-to: Your message of "Thu, 25 Mar 1999 21:10:42 PST." From: David Greenman Reply-To: dg@root.com Date: Thu, 25 Mar 1999 22:51:25 -0800 Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG >Is it possible to "dump" a "live" file system? (i.e. dump a file system >when the machine is in multi-user mode, with the filesystem that is being >dumped mounted read-write). Is it safe/recommended? > >It seems like this wouldn't be a great idea, since on a "live" file system >mounted read-write there may be pending writes, and it isn't clear how >dump would cope with that. Is it better/ok/safe to first remount the >filesystem read-only? > >I think I am a bit confused on this. > >Please include my address in replys. You're right: dumping a live filesystem is a problem and may result in a dump that isn't usable. One solution is 'filesystem snapshots', which is something that Kirk McKusick has been working on. In an efficient way it creates a read-only, static snapshot of a filesystem state that you can then do a dump of. Pretty slick. It has other advantages too, primarily when combined with softupdates it lets the system do the fsck in the background after a system crash, thus dramatically reducing the system downtime. -DG David Greenman Co-founder/Principal Architect, The FreeBSD Project To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message