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!! This is a Pre-alpha version. Expect breaking changes and bugs. !!

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diff-dd

This simple utility was created to reduce size of backup images of disk partitions. It is intended to be used in conjunction with dd or similar utility.

Synopsis

diff-dd help

diff-dd version

diff-dd create [-B BUFFER_SIZE] -i INFILE -b BASEFILE -o OUTFILE

diff-dd restore [-B BUFFER_SIZE] -d DIFFFILE -o OUTFILE

Create

Using diff-dd for backup requires the full backup image to exist. Differential backup is created with:

diff-dd create -i INFILE -b BASEFILE -o OUTFILE

The INFILE is a path to the file to backup differentially, the BASEFILE is the full image, and the OUTFILE is the file to which the changed data of the INFILE, compared to the BASEFILE, their offsets, and sizes will be saved.

Restore

The restoration means application of the changed data saved in the DIFFFILE, which is the differential image, to the OUTFILE:

diff-dd restore -d DIFFFILE -o OUTFILE

Options

-B sets the size of the buffer for the data of the input and output files (default is 4 MiB). The input data is always buffered. The output data is not buffered in the restore mode.

Example

First, the full image of the partition to backup has to be created:

dd bs=4M if=/dev/sda1 of=full.img

When the user decides to create the differential image, he or she runs:

diff-dd create -i /dev/sda1 -b full.img -o diff.img

If a data accident happens, the partition can be restored by running:

dd bs=4M if=full.img of=/dev/sda1

diff-dd restore -d diff.img -o /dev/sda1

The first command restores the old full image. The second one applies the differences.