Pi4 8GB RAM worth it?

[norbert_jordan (N. Jordan)]

Hi,
i’m right now on a RPI4 4GB, next to me a virgin 8GB Raspi.
If someone has experience, is it worth to swap the two SBC boards…some youtube videos i’ve seen could not show any performance improvements in comparision to pi4 4gb. Only i could think of OH which is java-based and in general more resource hungry.

Thanks for feedback,
Norbert

[Udo_Hartmann]

No, it doesn’t matter if it’s 4 GB or 8 GB, but you need to use the 64 Bit Mode for 8 GB, and that’s a bit tricky. There is no reason to use the 8 GB version for openHAB.
Of course you could use docker to use the Raspberry for more than just openHAB, but this also is not recommended.

[rlkoshak (Rich Koshak)]

An easy way to tell is to run htop or your resource monitor of choice. Look at the RAM readings. If you are using swap or running out of available RAM then you would benefit from more RAM. If not then more RAM isn’t going to change anything. Even though OH is Java, given all that it does it’s really quite easy on the RAM requirements once you get above the 1 GB RPi 2s and 3s have.

[mstormi (Markus Storm)]

Nope, it isn’t worth it. Even the introductory openHAB docs tell you.

[norbert_jordan (N. Jordan)]

Thanks a lot for the feedback, also for the hint regarding the DOCs. its really documented close to the my question. Will stay with Pi4 4GB.

Not sure what 8GB hardware will be used for…

[Anpro (Andreas Probst)]

I know this is an old topic but are there any updates on this? Because I’m thinking about getting a new Pi.
There are only two programs running on my Pi now - OpenHab and OpenV.
Is it safe to use 32bit version with 8gb pi model?

[mstormi (Markus Storm)]

There have not been any changes I’m aware of in the last 2 yrs.

[Anpro (Andreas Probst)]

Thanks for your reply - so I orderd a pi 4b with 4gb.
I will separate OpenHab and openv and use the new one only for OpenHab!

[peterhoeg]

I have an additional data point if you’re interested.

I am not using an rpi but instead an old laptop that happens to have 16GB of memory. I assigned 8GB to the jvm using -Xmx8G because the device isn’t running anything apart from zigbee2mqtt and openhab and this is how the JVM uses heap memory:

So not a lot to gain by splurging on additional memory.

Info: about 100 things, 500 items, 50 rules.

[milo (M)]

How can I generated such a diagram as you have done. It an read out the java heap memory usage in real time …?

[peterhoeg]

openhab exposes metrics in a format that prometheus will consume. You can see for yourself

curl http://openhab.host.name:9100/metrics

Official docs: https://www.openhab.org/addons/integrations/metrics/

Then it’s just regular grafana with this dashboard: https://www.openhab.org/addons/integrations/metrics/doc/dashboard.json

If you already have prometheus running (it’s phenomenal by the way!), it’s very straight forward to add this in.

If you don’t, there’s admittedly a fair bit of work to get it running.

[milo (M)]

Hello all,

the grafana dashboard is not available.

https://www.openhab.org/addons/integrations/metrics/doc/dashboard.json

Where can I find it?

[kristofejro (Kris)]

Here you go:
https://raw.githubusercontent.com/openhab/openhab-addons/main/bundles/org.openhab.io.metrics/doc/dashboard.json

[milo (M)]

Thanks

Anyhelp here

Openhab.host.name:8080/rest/metrics/prometheus not available

Quoted from the docs: /etc/prometheus/prometheus.yml): scrape_configs: - job_name: 'openhab' scrape_interval: 1m scheme: http metrics_path: /rest/metrics/prometheus static_configs: - targets: - 'openhab.local:8080' Replace openhab.local by the openhab host. Did you replace openhab.local in the file ?