[SOLVED] Starting with persistence

Setup, Configuration and Use Beginners
#1

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?

#2

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

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#3

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

#4

Not much
Mine is 2.18MB with 82 items persisted

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#5

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

#6

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

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#7

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:

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