[Digikam-users] about "synchronizing XMP sidecars and the digiKam database"

[Jean-François Rabasse]

On Sun, 24 Feb 2013, jdd wrote:

> Le 24/02/2013 16:15, Jean-François Rabasse a écrit :
>
>> My personal feeling (react if you think I'm wrong) is that the most
>> natural default is « replace » mode, not « merge » mode.
>
> yes, but as long as there is some sort of "get images backup" command, where 
> the contrary is true.
>
> If I find corrupted images (think of disk failure) and get back image backup, 
> I don't want to lose database metadata

Hum, I'm not sure to see exactly what you mean, JD.
Data moves, in backup/restore strategies, require to select a data source
and a data destination. And obviously, if on suspects the source to be
corrupted, the data transfert is to be avoided.
(Same if your database is corrupted or messy, you won't want to export all
metadata to images or sidecars.)

Anyway, no strategy can be based on failures, because you will never be
able to define a priori what failure or what kind of failure.
Also, given a standard image file, say 6 to 8 Mbytes, and the metadata
space, say 2 or 3 Kbytes, one sees that metadata occupies less than
0.5 % of the total file size. In case of a disk failure, e.g. bad block,
you're likely to loose parts of your image pixels data than metadata.
And your image is unuseable anyway.

So, disk failure => replace or repair => restore content from a backup.
IMHO

Jean-François