Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!olivea!uunet!zaphod.mps.ohio-state.edu!rpi!uupsi!ficc!peter From: peter@ficc.ferranti.com (Peter da Silva) Newsgroups: comp.unix.admin Subject: Re: SUMMARY: Backup while in multi-user mode Message-ID: Date: 24 May 91 18:30:47 GMT References: <1991May20.204327.17694@erg.sri.com> <690@silence.princeton.nj.us> <43617@netnews.upenn.edu> <1991May24.013214.2526@servalan.uucp> Reply-To: peter@ficc.ferranti.com (Peter da Silva) Organization: Xenix Support, FICC Lines: 44 In article <1991May24.013214.2526@servalan.uucp> rmtodd@servalan.uucp (Richard Todd) writes: > 1. "dump" preserves the access times on files, and "restore" restores the > files with the access times set correctly. "cpio" neither records the access > times in its archive nor leaves the access times of the files on disk > unaffected. Thus, "cpio" screws up any schemes one may have for locating > user files that haven't been accessed in, say, 6 months and automatically > moving them off to tape and deleting them. Your CPIO might have all those flaws. Ours doesn't. Ever hear of a program by the name of "pax"? > 2. "dump" handles files with holes in them correctly (the holes don't take > up space on the backup, and "restore" restores the files with holes correctly). > "cpio" doesn't. Having all your dbm files suddenly explode in disk usage > after having been brought back off of tape is considered bad form in some > circles... Again, a solved problem. (we don't use DBM, but our databases do have a similar behaviour) > 3. Just how were you planning to do restores of those incremental backups? We don't worry about deleted files reappearing, and it has not been a problem in general. We do not restore en-masse from major disasters anyway... it's always a good chance to tidy up old software, bring a system to the latest rev level of everything, and so on. > This means that you need to do > some extra work to make sure that all the stuff you got rid of once gets > gotten rid of again. This is a minor problem compared to the complexity of shutting down all the systems for the daily backups. I don't think we could work that way in any case, as we usually back up a lot of systems remotely over the network. > You can try to press "cpio" or "tar" into service as a backup program, but > it's not really the same thing... Until UNIX ships with a version of dump we can use, we don't really have an alternative. I'm really surprised that anyone with any significant number of machines is still using it. -- Peter da Silva; Ferranti International Controls Corporation; +1 713 274 5180; Sugar Land, TX 77487-5012; `-_-' "Have you hugged your wolf, today?"