Date: Fri, 29 Sep 2000 14:06:33 +0100 From: j mckitrick <jcm@FreeBSD-uk.eu.org> To: cjclark@alum.mit.edu Cc: freebsd-questions@FreeBSD.ORG Subject: Re: dump levels/incremental backups Message-ID: <20000929140633.A63505@dogma.freebsd-uk.eu.org> In-Reply-To: <20000928200709.J81242@149.211.6.64.reflexcom.com>; from cjclark@reflexnet.net on Thu, Sep 28, 2000 at 08:07:10PM -0700 References: <20000929033448.A59083@dogma.freebsd-uk.eu.org> <20000928200709.J81242@149.211.6.64.reflexcom.com>
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| Which means if you give a dump level of n, where n > 0, dump will | check /etc/dumpdates for the most recent dump of at a level less than | n. All files modified since that date are dumped. OK, this part I got right. I feel better now. | > What is the purpose of the 'Towers of Hanoi' number pattern? | | It is a trade between backup size and the number of restores that will | need to be done to any given point. The series in the manpage is, ah-HA! I get it. That's the answer I was looking for. | 3 2 5 4 7 6 9 8 9 9 ... | | For size concerns, notice that each dump contains no more than two | steps worth of changes. Now when we need to restore, say we have a | problem at, | | 3 2 5 4 7 6 | | This point of the cycle. To restore the filesystem, we start with the | level 0, then 1, then 2, then 4, and then 6. OK, so level 0 is a mass backup. Level 1 is weekly, and the others are for each day of the week. When a failure occurs, you start with 0 then 1. For the rest, and tell me if there is a simpler way to explain it, you use every other dump that will end on the last good backup. Either 3 5 7 9 or 2 4 6 8 9 This might be a silly question, but since there are more numbers in the series than days in the week, does that mean you should just do a level 1 and repeat the series when you reach 9 twice? | > Is the tar incremental backup simply based on comparing the modification | > times of the existing files to the stored ones? | | Don't use tar for backups, but I would assume so. What else would you | do? I thought maybe there was some built-in functionality to simulate this pattern we have been discussing automagically. I guess I just wasn't sure if there was another way to do it. I was making it more complicated than it really was :) I have been experimenting with flexbackup, but it seems the tar output for some reason isn't browsable by m-commander. My goal is to have an automated backup system that allows me to easily browse the archives if need be. This isn't a mission critical box, and these are more like archives than backups. But they obviously would be good to have if I *did* have a hardware failure of some kind. jcm -- "I drank WHAT ?!" - Socrates To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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