kevin@kosman.UUCP (Kevin O'Gorman) (02/14/88)
First off, my apologies to anyone who is waiting for me to respond to e-mail, because you may have a long wait unless you re-send whatever it is I'm supposed to be responding to. You'll see why. If you're the guy who's looking to use an Okidata-92, I have what you need, but you'll have to ask again. Now, the disk on my old 7300 (an externally cabled Seagate 80MB job) died a horrible death. I thought I was in pretty good shape, because I have ghengis here, a 3b1 I got in the fire sale, and I have a tape backup machine, and I had even gotten around to doing some pretty recent backups. I figured to drop a week's archived stuff, but only a day's news and mail. Wrong. I moved the tape backup from attilla to ghengis, and everything loaded up okay it seemed, and I went off for a week's trip to a client. I got the bad news when I dialled in: it seemed that all mail just got lost, that postnews couldn't find the distributions file (and died), that expire couldn't find NEWSGRP (and died) and that a bunch of other things were wrong too. All the missing pieces had to do with software I had installed at some point or other in the checkered career of this machine. To my mind, the culprit is the brain-damaged feature that they call "complete backup". To my chagrin, I really knew this already, and back when I backed up to floppies, which has the same problem, I had made my own solution called "Full system backup". The problem is that "complete backup" relies on the dates in the directories to tell it what to back up, so that it won't back up the Foundation Set, and such like stuff. It does this by comparing the dates (modified dates, I think) of the files with the date on /etc/.installdate. The problem is that some of the stuff I install was created a long time ago, and the modified dates are not changed by installing them, and so "complete backup" omits them, because I have had to do a complete system restore since then, changing the date. What's worse, the installation procedure for things like smail involve moving things around (like /bin/mail and /bin/rmail), so that they're in new places with the old date and "complete backup" doesn't notice these either. Restoring such a backup is a learning experience indeed. There's a sort of Monte Carlo effect to the result. Not real reassuring. The solution I used for floppies was to modify the floppy backup script to create a new option called "Full System Backup", so that it backed up EVERYTHING except a few specific files. The omitted files were ones which were not part of the Foundation Set, but were on the disk after a system build. The neat part of this scheme is that you can them use the resulting backup set in place of the Foundation Set in the procedure for building a system from scratch. Voila: a completely rebuilt system with no missing files, and no fussing with the UA to install package after package, but even the UA files are right when you're done (if you care). Yes, the Foundation Set is just a cpio archive on system-formatted disks. You could do the same thing with find / -print | fgrep -v '<exceptions>' | cpio -ocBv >/dev/rfp021 The only disadvantages were shared by all massive floppy backup schemes: too many floppies to keep loading, it took too long, and there was the ever-present danger that one of the floppies would go bad, and your restore would not complete (it happened to me once). Besides, I never got around to actually backing up to those 50 to 90 floppies after the first two or three times. I just couldn't stand the boredom. Thus the acquisition of the Tape Backup. So, let this be a warning to you all: do better backups than what AT&T has provided. Finally, a question: has anyone with a Tape Backup figured out a good way to deal with this? Right now, I'm thinking I will backup / by name, and if I ever have to rebuild from that backup I'll have to restore the entire Foundation Set, then the Tape Utilities, and finally restore the tape. It's not too bad, but is there a better way?
wilber@alice.UUCP (02/17/88)
kevin@kosman.UUCP writes: > Finally, a question: has anyone with a Tape Backup figured out a good way to > deal with this? Right now, I'm thinking I will backup / by name, and if I > ever have to rebuild from that backup I'll have to restore the entire > Foundation Set, then the Tape Utilities, and finally restore the tape. > > It's not too bad, but is there a better way? Yeah, tape backup on the 3b1 is pretty lame. First, you *must* change /etc/.installdate to be Jan 1, 1970. (Or whatever UNIX thinks the beginning of time is -- I think that's right.) Second, mung the shell script in Tbackup.sh to back up all the stuff you really want to have backed up. I changed mine to back up all regular files and directories, including the stuff in /bin, /usr/bin, and /etc. Even with this I'm not sure that every thing I'd ever want backed up is *really* being backed up but it sure is better than how it came out of the box.
mark@gizzmo.UUCP (mark hilliard) (02/18/88)
Keven, this is the way that I do it. I back up by name (/*), then after
a system crash, I reload the foundation and tape drivers, then a restore by
name (/*) brings the entire system back. It is not the best way perhaps, but
It does work.
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Mark Hilliard seismo!rochester!kodak!gizzmo!mark
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