When inode change time changes?

[Artem Kuchin]

I am having tough time with backup system.

I use gtar (gtar because it has incremental
backups, and tar does not)

I use inode change time in order to backup
all changed files. I have notices that some
files are always backed up even if they did not
change. For example all mysql database.
I checked their file change time and it is not
changed, howeever, inode change time changes
on every mysql restart.

Maybe someone can englighten me when
inode change time changes? What must be done
with file to change it (except writing to it)?
I tried chmoding - it does not affect inode time.


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Regards,
Artem