How to optimize the cloning of a disk with a big empty ext3 partition?

Stephen Samuel (gmail) darkonc at
Sat Jun 20 04:39:32 UTC 2009

A program like partimage will copy only the sectors that are already in use,
but it
requires that the destination partition be at least as big as the original
it would be required to relocate used sectors that are near the end of the

The only real way around your problem would be to resize2fs to resize the
(not the partition) to  a bit over 1GB At that point you could safely copy
only the first
Gig of the partition (whatever size you changed the filesystem to).  You
could then
(if you wanted to) resize the filesystem back to fill the partition.

If you just need the data from the partition archived, and don't need it to
be live,
then you can just use partimage to dump the used sectors, into a file...
When you
need to reconstitute the filesystem, however, partimage will want to create
a filesystem
the same size as the original.

On Fri, Jun 19, 2009 at 4:42 PM, Gregoire Gentil <gregoire at>wrote:

> Hello,
> I need to duplicate a huge number of identical 8GB SD cards on which I
> have 1GB of data at the beginning of the disk on various partitions and
> then a 7GB ext3 partition which is rather empty (just a few MB of data).
> The duplicator device enables me to select which sectors I can
> binary-duplicate. I would love to divide by 8 my duplication time, by
> duplicating only the first GB and then the beginning of the 7GB ext3
> partition.
> When I do a mkfs.ext3, I see that the super-block is written to various
> locations of the partition which is not good for the optimization I
> would like to do.
> Anyone can advise how I could optimize my duplication? What are my
> options? Would it be the same situation for ext2? Meaning where is the
> journal written on the ext3 partition? Is there a single version or
> multiple versions?
> Thanks in advance for any answer or pointer,

Stephen Samuel  Software, like love,
778-861-7641                              grows when you give it away
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