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Date:      Sun, 04 Nov 2012 19:49:24 -0800
From:      "Ronald F. Guilmette" <>
Subject:   Re: Questions about dump/restore to/from DVD media
Message-ID:  <>
In-Reply-To: <>

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In message <>, 
Polytropon <> wrote:

>> But as I said (above) to make this really work right, dump & restore really
>> need to have -z options, and do the zipping/unzipping internally.  Only
>> if this were available could dump properly deal with end-of-media on any
>> given output volume, I think.
>The problem is that delegating compression to a "sub-task" would
>imply that dump cannot precisely adjust its output to match the
>media size (as the limit is now defined by how good the compression

Correct.  We have both just said the exact same thing in different ways.

In order to have _compression_ of the dump data _and_ still be able to
divide the (post-compression) data into nice proper 2KB chunks (as required
for DVD+/-R writing) the compression step itself would need to be integrated
into the dump program itself (and then, for symmetry, if for no other
reason, into restore as well).

>Using dump + restore
>means to operate on partitions. Make the system one partition - deal
>with one partition. Make many partitions - need to deal with them

Good point.

>> (I hate to say it, because in general I loath & despise Windows, but even
>> Windows has a built-in facility for making a single backup of an _entire_
>> system, and in a single step, *and*, I presume in a space-efficient manner.)
>That would be a task for dd. :-)

Sorry?  I am not following you.

How could dd ever substitute for the intelligence of dump(8), and specifically
how could it avoid copying of blocks that are ``in'' the filesystem but which
are not currently _allocated_ by the filesystem?

(I am also not persuaded the dd could handle multiple partitions any better
that dump(8) currently does... which is to say not at all, really.)


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