From owner-freebsd-questions@FreeBSD.ORG Mon Oct 31 19:38:18 2005 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id A1D7616A41F for ; Mon, 31 Oct 2005 19:38:18 +0000 (GMT) (envelope-from paul@gromit.dlib.vt.edu) Received: from gromit.dlib.vt.edu (gromit.dlib.vt.edu [128.173.49.29]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2A82D43D46 for ; Mon, 31 Oct 2005 19:38:02 +0000 (GMT) (envelope-from paul@gromit.dlib.vt.edu) Received: from zappa.Chelsea-Ct.Org (pool-70-110-1-195.roa.east.verizon.net [70.110.1.195]) by gromit.dlib.vt.edu (8.13.4/8.13.4) with ESMTP id j9VJbiBx039753 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 31 Oct 2005 14:37:46 -0500 (EST) (envelope-from paul@gromit.dlib.vt.edu) Received: from zappa.Chelsea-Ct.Org (localhost.Chelsea-Ct.Org [127.0.0.1]) by zappa.Chelsea-Ct.Org (8.13.4/8.13.4) with ESMTP id j9VJbX2R001613 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 31 Oct 2005 14:37:34 -0500 (EST) (envelope-from paul@gromit.dlib.vt.edu) Received: (from paul@localhost) by zappa.Chelsea-Ct.Org (8.13.4/8.13.4/Submit) id j9VJbW9P001612; Mon, 31 Oct 2005 14:37:32 -0500 (EST) (envelope-from paul@gromit.dlib.vt.edu) From: Paul Mather To: freebsd-questions@freebsd.org In-Reply-To: <20051031184123.8C39116A429@hub.freebsd.org> References: <20051031184123.8C39116A429@hub.freebsd.org> Content-Type: text/plain Content-Transfer-Encoding: 7bit Date: Mon, 31 Oct 2005 14:37:32 -0500 Message-Id: <1130787452.1396.16.camel@zappa.Chelsea-Ct.Org> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 FreeBSD GNOME Team Port Cc: Csaba Henk , Eric Schuele Subject: Re: backup strategies 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: Mon, 31 Oct 2005 19:38:18 -0000 On Mon, 31 Oct 2005 18:59:21 +0100, Csaba Henk wrote: > On Mon, Oct 31, 2005 at 10:32:02AM -0600, Eric Schuele wrote: > > The online manual mentions it in 16.13. Wouldn't hurt for it to be > in > > the man page as well. > > Oh, yeah, thanks. > > This makes things clear. I missed this somehow. > > > AFAIK FreeBSD 5.0+. Other *BSD as well, i believe... but someone > else > > would have to answer that. > > > > >(AFAIK, softupdates is supported also in other members of the BSD > > >family, yet the NetBSD dump manpage didn't have such a -L flag...) > > OK, as I understand now, softupdates might be available for other > BSD-s, > but snapshotting is not a "free bonus" which comes with softupdates, > but > a new innovation based on that... and is a true FBSD innovation. So > I'd > guess it's still a unique thing. Not quite: NetBSD also features softupdates and also supports snapshots (though I don't know how stable it is, as I've never tried it on my NetBSD system). The snapshot interface under NetBSD is different from that on FreeBSD: you can create a snapshot "device" that can be used to snapshot a file system. (You can then mount or dump the snapshot device to get a consistent image/backup of the filesystem being snapshotted.) The main difference appears to be you are not limited to snapshots residing on the same file system of which you are taking a snapshot, which could be handy for near-full active filesystems. See fss(4) and fssconfig(8) man pages under NetBSD for details. The other thing to note about FreeBSD snapshots that I don't think has been mentioned is that they are only supported on UFS2 filesystems, meaning they are unavailable under FreeBSD 4.x and earlier (or on older filesystems created by those older versions of FreeBSD). I've been using snapshots under FreeBSD 5 onwards, pretty much since the feature became available, and have only ever had a problem once (due to a race condition in the snapshot code, it was surmised), and that was with a nightly automated network backup of snapshots of all filesystems on a system with high disk I/O. I find it to be a really valuable feature. Cheers, Paul. -- e-mail: paul@gromit.dlib.vt.edu "Without music to decorate it, time is just a bunch of boring production deadlines or dates by which bills must be paid." --- Frank Vincent Zappa