Systemback

Incremental backup question

Asked by David

Hi

Systemback is a very useful utility. I am enjoying using it. I have a couple of questions on Systemback's incremental backups that I wondered if someone could help with? On my system, Systemback is set to backup incrementally. I've been using it for the past month and have taken weekly restore points. I expected the first backup would be quite large and subsequent ones smaller as the new increment was backed up. But that's not what I've seen, as all the backups are similar size and the more recent ones are in fact slightly larger. Why are the newer restore points not smaller in size ?
Also I understand that older restore points are deleted once the maximum number of temporary restore points is exceeded. How is that possible if the newer backups are increments, as surely it then wouldnt be possible to restore the system ? Have I misunderstood how Systemback is working?

Regards

David

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Kendek
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Best Kendek (nemh) said : 		#1

The incremental method means that the Systemback uses hard links between restore points when it is possible. For example if the /bin/bash file is the same as the /storage/dir/Systemback/old_restore_point/bin/bash, the Systemback does not create a new copy of this file, but create a new link, pointed to the file data in the previous restore point. The copied file is still accessible, as long as at least one link that points to it still exists. So if you delete an old restore point, then you just delete a link, not the data.
And that is why the file manager showing that the restore points are the similar sizes. Please read this wiki page:
https://en.wikipedia.org/wiki/Hard_link

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David (d-billingham) said : 		#2

Thanks Kendek, that solved my question.

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David (d-billingham) said : 		#3

Clever stuff, but useful to know how it works. Thank you for taking the trouble to let me know

David