No habmin chart from some data in openhab2


My charts are working well in habmin, but I tried to add some more data to display.
When I try to chart these data, charts stay blank. I don’t know what I’m missing.
The data I add (The two first vary from 0 to 65535) are transmitted through MQTT.

The *.items file : (first I tried with <sun> instead <number> but no difference)

    Number  Dist11_UVA      "UVA Dist 11 [%d ]"             <number>        (Group_UV,Graph_UV,Graph_Test)  { mqtt="<[serveurmqtt:ESP_NR/Capteurs/UVA/Dist11:state:default]" }
    Number  Dist11_UVB      "UVB Dist 11 [%d ]"             <number>        (Group_UV,Graph_UV,Graph_Test)  { mqtt="<[serveurmqtt:ESP_NR/Capteurs/UVB/Dist11:state:default]" }
    Number  Dist11_UVIndex  "UVIndex Dist 11 [%.2f ]"       <number>        (Group_UV,Graph_UV,Graph_Test)  { mqtt="<[serveurmqtt:ESP_NR/Capteurs/UVIndex/Dist11:state:default]" }
    Number  Dist11_Batt     "Batt Dist 11 [%d mv]"          <battery>       (Group_Batt,Graph_Batt,Graph_Test)      { mqtt="<[serveurmqtt:ESP_NR/Capteurs/Batterie/Dist11:state:default]" }
Group   Group_UV
Group   Group_Batt

Group   Graph_UV
Group   Graph_Batt

The rrd4j.persist file:

Group_UV* : strategy = everyUpdate, restoreOnStartup

The data are fine transmitted through MQTT

The *.rrd files associates to this items are well created in /var/lib/openhab2/persistence/rrd4j/ and if I delete it, it reappears.

The /var/log/openhab2/events.log and /var/log/openhab2/openhab.log show some time error but nothing to do with this.

Any clue where it could comes from? What did I miss?

The rrd4j persistence MUST include the everyMinute strategy, see:

Thanks for your answer.

I dont understand I removed the “everyMinute” from some other items groups and they still charting well.
Is this because they had some record from before when “everyMinute” was activated for them?

Is there a way to only store data when a change occurs? Not on a time frequency?
I don’t know if I understand all explanations of your link, some data are loosed and old data are averaged by openhab when going forwards?

(Sorry for my English)

Not with rrd4j

If you want something more flexible and nice graphs then see:


Yes, fine data is lost over time and averaged. The rrd4j database will not grow infinitely in size

You were right, now my charting is working with this new items! Thank you again :slight_smile:

I’m interested in InfluxDB but by following your link I read this

These are the special steps to install InfluxDB and Grafana on a Raspberry Pi 2 or 3, the older Raspberry Pi 1 is not suited due to it’s ARMv6 architecture .

My openhab2 server run on a cute Raspberry Pi (the first) revision B (Raspbian Jessie). So I understand that InfluxDB need too much resources to run on it? What do you think could be better than rrd4j for my small RPi?

I use SQlite for my other services (very light against MySQL)