Hi.
when i use the InfluxDB persistence layer in stead of the RRD4j i get strange graphics. The value “0” seems not to be stored in time. I get only a line between the changed values (resulting in sawtooth charts). this happens for example if i want to show a CV-pomp-power wich go’s from “0” to “15” watt.
If i use RRD4j it looks good, but then i lose data if i restart the OH system.
Can you elaborate on this? You shouldn’t be losing any previously persisted data at all.
as soon as i restart the PI4 with OH3 (unplug power for a short time) and i go in the chart created with RRD4j again, all history is gone. Way … i realy don’t know.
between the left arrow and the upper right, the values should show “0” 
What is your persistence configuration ?
Looks like for the red one every change is being stored but not a value e.g. every X minutes ?
i’m working with OH3. Where can i find the persistence configuration. it’s not in the OH3 UI…
Here’s the relevant documentation, so presumably you’re using the defaults.
This really shouldn’t be happening.
The documentation states:
do you really unplug your Pi to restart it or do you first shut it down and then unplug it.
The first one shouldn’t be done. This can cause damage to the filesystem on the SD card.
Do you use openhabian with preconfigured zram usage ?
I do not exactly know if the zram writes back to the filesystem only ones the system is being shut down or continously. As writting to the system is being limited to have as less write cycles as possible it could be that it writes back to the system only in case the shutdown is done via system command and definitely not triggered by unpluging the system without first doing a shutdown.
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oeps … i reset via disconnecting the power 
and don’t use zram.
Beside of this all, can you tell me how the graph is showing this strange behavior if i use InfluxDB persistence ?
i want to look in the persistence config but according the documentation:
Persistence Strategies are configured in a file named <persistenceservice>.persist , stored in $OPENHAB_CONF/persistence .
with OH3 there is nothing stored in $OPENHAB_CONF/persistence . Where can i change the strategies in OH3?