[SOLVED] Starting with persistence

Good morning, I’m starting to add a persistence engine on my OH2.5.0M2 but I have some questions:

  1. since the update to M2 milestone the memory request is grown and now I only have 170MB free on my raspberry 3.
    Is it enough to configure what is needed?

  2. what is needed to have a persistence? I installed an external SSD and I’d like to install MariaDB but I read in not possible to share the instance with another application (like nextcloud)

  3. My goal is to restore some items status at the start and to have a chart of my energy meter and thermostat temprature, what is the best persistence engine?

Use mapDB for this purpose.

Use rrd4j

These two persistence engines are very well integrated into OH and will not add any load on your PI3


How much data space does rrd4j need for the round robin database?
Linux does not behave well if it runs out of disk space.

Not much
Mine is 2.18MB with 82 items persisted

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Ok, thaks for your time! I configured my first item with mapdb and it works.
Where are stored the persistence? I’d like to move on ssd disk to preserve my sd

On a Linux system you can find the files in here.


Thank you for your time! You was precious. Now my dummy switch are persistent at restart and I moved the “persistence” folder to the SSD with a symlink. Next stop rrd4 and charts :smiley: