rrd4j does not store data

Dear Openhab-community,
I have a strange Problem with the rrd4j persistence:
The rrd4j persistence is started and in the debug log file I can see that the values are stored.
But the rrd files created in the folder /etc/rrd4j dont grow.The files for numbers stay at 28kB.
The files are updated every minute but there are no values.
When I create a chart in the sitemap, the chart ist empty.

I am using OH 1.8.1.

Any idea would be great.

Thanks
Stefan

Rrd4j is a fixed size db. I don’t think it is supposed to grow. Are you using an every minute strategy? If you dont save every minute rrd4j will not generate charts.

Thanks for the answer,
The problem seems to be in the chart.
When opening just the chart in the browser I got the error:
Could not initialize class sun.font.FontScaler

What can be the reason for this?
I just installed the java jdk.1.8.0_71.

Many Thanks
Stefan

I fixed it by installing the latest Java version.
Something was wrong with the older Version.