RRD4J loggin only once per 6 hours

RRD4j need to record every minut, but it possible to make RRD4J log only once per day, to stretch the recording to a ½ to a year e.g.?
I like to do use it for logging the nutrition of my miflower plat sensor over several months.

You can define the the strategie "everyDay : "0 0 0 * * ?"
and choose the propper persistene-binding.

I dont quit understand,
According to https://docs.openhab.org/addons/persistence/rrd4j/readme.html:
“The strategy everyMinute must be used, otherwise no data will be persisted (stored).”

So I need to use every minute, or do I misunderstand?

No, you don’t missunderstood.

Rrd4j is a special DB, like it’s name says it is a RoundRobbinDB, it never grows.
In order to set it up for daily steps, use archive one to store a value every minute for 24 houres and use a secondary archive to store a value for each day. Note that you have o setup the exact amount of days you want to store. Rrd4j will not store more then that.
Using such a setting rrd4j will hold data for the last 24 houres (every minute) and the desired amount of days (every day)

ok, Can I use RRD4J as the secondary DB? I don’t the the data for more than one year, if so, wound’t it conflict with the requirement of logging every minute?

You don’t have to set rrd4j as the default DB.
Concerning your desired setup, as said above rrd4j does require to persist the actual data every minute, no way around that.
However you only need to KEEP the minute wise data as posted above. If you need assistance in the actual setup of your db just yell.