Date: Fri, 15 Nov 2002 22:43:46 -0600 From: "Mike Loiterman" <mike@ascendency.net> To: <freebsd-questions@FreeBSD.ORG> Subject: Re: restore question Message-ID: <004801c28d2a$c4e52690$0302a8c0@mike>
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 > There IS a program similar to Ghost with respect to making an > image. It's called "dd" and it's already installed on your FBSD > system. Run "man 1 dd" for options. > > Bear in mind that if you want an image of your whole disk, you'll > need the 2nd one to be at least equal in size, but you will lose > any part of the > 2nd HD that is larger than HD #1 (I think Ghost does that too > -- or used to). dd can be limited to imaging only a slice > however..... > > This questions comes up monthly and the archives has numerous > postings over the past several months that will fill more > details..... Yes, the question comes up many times; yet the right answer keeps lacking. :) Before I asked, I had, of course, done a bit of searching. And found that there are many disadvantages to using "dd". For one, using disk-blocks, instead of reading files sequentially, like tar and Ghost do, enhances the risk of data-corruption. For two, with "dd" you need to unmount filesystems first. Which makes it pretty useless on a production server. Yeah, like I can really afford to have my /usr slice be absent for half-an-hour. I think not. :) Actually, we are talking about backup, but the real issue is restore. Everybody can make a tar of the root system, or a dd image. Sure. Restoring it, however, in a manner that will yield you a bootable, instant runnable system, now that is another matter. And what to do with special cases like /dev? In all my perusing the net, I have yet to encounter one solution that said: "This is how you can make a full system backup, with this image, that you can immediately restore on a blank harddisk, and have your system up and running again." Many suggestions I read about ways to backup. But, like I said, restoring is the real issue. I can backup /proc for sure; the wisdom of restoring it on a life system, however, is another matter. That is why the only clean way of doing this, would be to make a disk-image, like Ghost does. And Ghost, so unlike dd, does NOT use disk-blocks, but reads files sequentially. When making a disk image, Ghost basically just does several partition images, and then adds partition table info to the overall disk image. No need to "zero" out the disk first, like with dd, so as not to have it waste too much space. Still looking... - - - Mark I agree with Mark completely. I posted a similar question a while ago. I'm looking at it from the perspective of simply swapping out disks. For example I have an old 2 gig drive the I wash to replace with a new 20 gig drive. It appears to me, unfortunately, that the only way to really do this is to setup the new drive with proper slices and partitions as appropriate and then do a dump and restore onto the new drive. In terms of doing a restore, I've wanted a "ghost" type of program for a *long* time. There has to be an easier way? Perhaps this is troublesome because of the way FreeBSD operates in terms of slices and partitions rather then just partitions. I *believe* that the copy of Ghost I have will work on Linux boxes, but I could be mistaken. ........................................... Randomly Generated Quote: 'We already *know* who your friends and family are.'-AT&T Mike Loiterman PGP Key 0xD1B9D18E http://www.ascendency.net -----BEGIN PGP SIGNATURE----- Version: PGP 7.0.4 Comment: Message digitally signed by Mike Loiterman iQA/AwUBPdXNAmjZbUnRudGOEQLrDQCg4Po/rcKkkW2Wgn/VYsfdVGWf5OcAniXK JQQp8mqiApELCKmCWZLjKvpn =U7+l -----END PGP SIGNATURE----- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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