From owner-freebsd-questions Fri Sep 18 16:17:34 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id QAA28051 for freebsd-questions-outgoing; Fri, 18 Sep 1998 16:17:34 -0700 (PDT) (envelope-from owner-freebsd-questions@FreeBSD.ORG) Received: from cm110119.cableco-op.com (cm110119.cableco-op.com [206.24.110.119]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id QAA27957 for ; Fri, 18 Sep 1998 16:17:04 -0700 (PDT) (envelope-from jwg@cm110119.cableco-op.com) Received: (from jwg@localhost) by cm110119.cableco-op.com (8.8.8/8.8.8) id QAA01905; Fri, 18 Sep 1998 16:18:28 -0700 (PDT) (envelope-from jwg) Message-ID: <19980918161827.65051@cm110119.cableco-op.com> Date: Fri, 18 Sep 1998 16:18:27 -0700 From: Jeff Gray To: brian@worldcontrol.com Cc: freebsd-questions@FreeBSD.ORG Subject: Re: Root Disk Backup. References: <36029DED.100E0A16@open.org> <19980918124926.A1848@top.worldcontrol.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.89.1i In-Reply-To: <19980918124926.A1848@top.worldcontrol.com>; from brian@worldcontrol.com on Fri, Sep 18, 1998 at 12:49:26PM -0700 Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Hmm.. why not use rdist ? -can be done without shutting down as it works even on executing files. from man rdist Rdist is a program to maintain identical copies of files over multiple hosts. It preserves the owner, group, mode, and mtime of files if possi- ble and can update programs that are executing. Rdist reads commands from distfile to direct the updating of files and/or directories. I *think* rdist is available on both SCO and BSD. Runs over tcp/ip jeff On Fri, Sep 18, 1998 at 12:49:26PM -0700, brian@worldcontrol.com wrote: > On 0, Robert Clark wrote: > > I'm trying to establish a set of tools that will minimize downtime when > > a root disk fails. > > Not because root disk failure is a frequent occurance, but when it > > happens, its always a key system at a bad time. > > > Questions / assumptions: > > FreeBSD can backup a HD even if their is no FS FreeBSD recognizes? (I've > > worked with a few (non UNIX0 tools that need a (PC-style) partition > > table to do their jobs.) > > As long as the geometry of the replacement drive is the same, does this > > approach sound feasible? > > yes. I do it all the time. > > > What commands / programs could I use under FreeBSD? > > cat /dev/rsd0 | gzip | > backupcopy > > > Is anyone else out there doing anything like this? > > Yes. > > > In order to keep the amount of time a station is down during root-disk > > backups, I'm entertaining the idea of making the initial copy a disk to > > disk process. (And dump the second disk to tape a few minutes later.) I > > was hoping that disk to disk would be quite a bit faster than disk to > > tape. > > Yes. Disk to Disk is far faster, and IMHO more reliable. > > > Compound Question: (More for info than for need.) > > > If you dump a binary image of said HD, compression won't do much. Even > > if the HD is only 10% in use, the compression algorithm won't know what > > is files, and what is deleted files. > > I generally get around 50% compression with gzip on the raw size of > the disk. bzip2 is too slow because it doesn't like compressing large > areas of similar data (blank sectors). A fully used filesystem might > not have this problem. > > > Dumping a binary image of a "washed" disk would seem to be faster. > > I find copying a disk to disk runs at about a constant rate regardless > of the data. The compression time can change. > > > Washed areas should be easier to compress. > > Yes gzip, No bzip2. > > -- > Brian Litzinger > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-questions" in the body of the message To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message