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Date:      Fri, 15 Nov 2002 09:15:00 -0600
From:      "Jack L. Stone" <jackstone@sage-one.net>
To:        Mark <admin@asarian-host.net>, <freebsd-questions@FreeBSD.ORG>
Subject:   Re: restore question
Message-ID:  <3.0.5.32.20021115091500.010abd98@mail.sage-one.net>
In-Reply-To: <200211150425.GAF4PFI21317@asarian-host.net>
References:  <LGELIHAAGFPLCGDLOGMAIEKPCNAA.richard@radecom.nl> <020901c28b6f$f0b241c0$1200a8c0@gsicomp.on.ca> <127.0.0.1.20021114195745.01099888@mail.sage-one.net>

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At 05:25 AM 11.15.2002 +0100, Mark wrote:
>----- Original Message -----
>From: "Jack L. Stone" <jackstone@sage-one.net>
>To: "Mark" <admin@asarian-host.net>; "Matthew Emmerton"
><matt@gsicomp.on.ca>; "R. Zoontjens" <richard@radecom.nl>;
><freebsd-questions@FreeBSD.ORG>
>Sent: Friday, November 15, 2002 2:57 AM
>Subject: Re: restore question
>
>
>
>> 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 missed this earlier. You say:

"That is why the only clean way of doing this, would be to make a
disk-image, like Ghost does."

I'm unaware of any backup that takes longer than a nanosecond where files
will not have changed on a system by the time you are done making an image.
Does Ghost sync the files again at the end of the backup....??? I am not
anti-Ghost, just pro-dump/retore and dd after that and tar after that......
because I feel I can trust them with my data.

Best regards,
Jack L. Stone,
Administrator

SageOne Net
http://www.sage-one.net
jackstone@sage-one.net

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