Rrd4j or influxdb question

My plan is using Influxdb persistence for Grafana using http statement from http binding for opening Grafana pages on OH3.
Are all items, things etc. previous and new stored after iInfluxdb installation still in rrd4j database please ?
Can I lost all previous items,things etc. definitions after switching to Influxdb persistence ?
Is influx only used for persistence purposes, not definitions ?

  • Platform information: RPi4 4GB, raspbian bullseye
  • openHAB version: 3.3

InfluxDB as well as RRD4J is a persistence service. All persistence services can be used independently and with different configuration per item. It’s up to you whether same or different data is persisted.

Naturally, data can only be persisted once a persistence service is configured, so you won’t see any persisted data from wiithin rrd4j in influxDB and therefore neither in Grafana.
There is no easy way to “copy” old data from one persistence service to another.

There are slight differences between persistence services, e.g. rrd4j is “round-robin” (i.e. old data is erased when new data is written) and there are certain blocks of time with different temporal resolution (i.e. the older the data gets, the less accurate the data is). InfluxDB will consume more diskspace the more data is stored, mapDB as another persistence service will only store the current value, so one can restore the last known value through startup.

1 Like

Hi Udo,
thanks for clarifying. I don’t need all previous historical persistence data to convert from rrd4j to Influxdb. This is a horrible way.

I propose, that new archives (persistence values) would be written after installation of Influxdb persistence only to Influxdb series. Then rrd4j persistence can be deactivated / erased from OH3.
Influxdb can be used with nice Grafana. Disk capacity is not a problem. Rotation of Influxdb series can reduce the storage.

Definitions of things, items etc. stays in OH3 in json format not affected from persistence change.
Please confirm my proposal.

Correct. Persistence services are entirely separate from configuration of things/items/etc. openHAB simply outputs the item state updates to whatever persistence services you set up.

1 Like

All clean. Thanks.