RRD history lost on reboot on Alix board (nanoBSD)

[LucaTNT]

Hi,
I've recently moved my VirutalBox-based install to a hardware box, an Alix Board. I was able to import everything from the old setup, including my RRD history.
I also set the periodic RRD Backup setting in System/Advanced/Miscellaneous to 3 hours, and yet the board lost my history twice due to power outages.

I can always re-import my old VirtualBox RRD history, but of course doing so I lose recent stats.

Is this a bug or am I doing something wrong?

Luca