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Date:      Sun, 4 Nov 2012 17:48:24 -0800
From:      Mehmet Erol Sanliturk <m.e.sanliturk@gmail.com>
To:        "Ronald F. Guilmette" <rfg@tristatelogic.com>
Cc:        freebsd-questions@freebsd.org
Subject:   Re: Questions about dump/restore to/from DVD media
Message-ID:  <CAOgwaMvoNCTi7AkMtjw0+CAaSTFHfAE5GW+pkMh+4LdR00-9rA@mail.gmail.com>
In-Reply-To: <20880.1352077018@tristatelogic.com>
References:  <20880.1352077018@tristatelogic.com>

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On Sun, Nov 4, 2012 at 4:56 PM, Ronald F. Guilmette
<rfg@tristatelogic.com>wrote:

>
> I would like to make a backup of one of my systems using dump(8) in order
> to be sure that I get everything, including all of the obscure file
> attribute
> bits.
>
> I would like to make this backup to a _minimal_ number of DVD+R disks.
>
> What's the proper procedure for this?
>
> In the dump(8) man page, I see the following example:
>
>   /sbin/dump -0u  -L -C16 -B4589840 -P 'growisofs -Z /dev/cd0=/dev/fd/0' /u
>
> There are several problems with this example, as far as I am concerned.
>
> First I have no particular interest in, or need for _either_ an ISO 9660
> _or_ a UDF file system on my backup media.  And in fact, that seems to me
> as if it is likely to be an utter waste of (precious) space on the backup
> media.  Can't I just put the output of the dump command _directly_ onto
> the output DVD+R media?  If so, how would I do this?  Would a command
> such as the following work?
>
>    /sbin/dump -0u  -L -C16 -B4589840 -P 'dd of=/dev/acd0 bs=2048' /u
>
> If not, why not?  (I  already know for sure that I can _read_ everything
> off of a DVD+R using just dd, so it seems logical that I should likewise
> be able to write an entire CD using just dd, but I suspect that there may
> be more to it that this, since I've never seen any references or examples
> anywhere of anybody writing either CDs or DVDs using dd.)
>
> Actually, I just noticed in the dump manpage the -f option.  So would this
> work in place of the above command line?
>
>    /sbin/dump -0u  -L -C16 -B4589840 -f /dev/acd0 /u
>
> And if THAT works, then can dump properly sense the actual end-of-media on
> /dev/acd0, so that the -B option can just be ommitted?
>
> Another issue is that I most definitely want to use an absolute minimum
> of DVD+Rs to store the dump.  So I am wondering how I might be able to
> wedge gzip into this whole process.  Could I do something like this?  If
> not, why not?
>
>    /sbin/dump -0u  -L -C16 -B4589840 -P 'gzip | dd of=/dev/acd0 bs=2048' /u
>
> Lastly, I want to make a backup of one entire _system_... not just one of
> the several partitions that compose that system.  How exactly can I do
> this?  I mean sure, I can back up each partition separately, using dump,
> one at a time, but if I do that then the logical implication would seem
> to be that on the last DVD+R used to make a backup of each of the
> partitions,
> there could possibly be a lot of unused/wasted space which could have been
> used to store the first part of the dump for the next partition in turn.
> Is there any way to effectively deal with _this_ issue?
>
>
> Regards,
> rfg
>




Assume one file will NOT be copied more than ONE DVD , i.e. , each file
will be completely recorded on one DVD :

http://en.wikipedia.org/wiki/Cutting_stock_problem


Thank you very much .

Mehmet Erol Sanliturk



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