Minimum RAM Requirement - 1GB is not enough

Installation
1

My original installation on a RPi 4 with 1GB worked well for about 10 months.

After an update in mid December 2025 instability was introduced.

The ZigBee2MQTT module would freeze, logs were sometimes showing a communication problem to the ZigBee USB dongle, but otherwise just stopped updating with the freeze.

Here is the HW used: (latest)

Installation method: Home Assistant OS

Core: 2026.3.4

Supervisor: 2026.03.2

Operating System: 17.1

Frontend: 20260312.1

Coordinator: EmberZNet – 0xb43522fffe0cf004 - Revision: 8.0.2 [GA]

Initially HA would last days before freezing again. Recovery was by rebooting the entire board only, restarting ZigBee2MQTT would work before freezing within 2 hours.

Over time (4 months) after a system reboot, uptime of ZigBee2MQTT module became shorter and shorter - from days to 3 hours despite my attempts to fix it.

Attempts to Fix

Replace the USB cable to the dongle, ensure USB 2.0 port used - no change.

Replace the USB cable to the dongle with a USB 2.0 hub - no change.

Upgrade the dongle firmware to latest version - no change.

Replace the dongle (cloned the MAC, latest firmware installed) - no change.

Relocate the HA and dongle to different location in house - no change.

Disable Bluetooth - no change.

The Fix

Replaced the RPi4 1GB with a RPi 2GB RAM.

Note: The original SD card with original installation was used throughout this process.

Conclusion

1GB of RAM might have been ok in 2025 but now it does not cut it.

Usage of RAM showed up to 85% usage with the 1GB Pi, now after Pi swapped it shows around 70% (1.3/2GB).

2

You might have been able to work around it with more SWAP via ha os config swap but there’s a reason the docs say

make sure to choose a model with at least 2 GB of RAM

I find HA to be bloated but what can you do. I wouldn’t have recommended a pi. Did you already have it?

4 Likes
3

I did miss the 2GB RAM notice. Long lesson learnt there.
I did buy another Pi for this but you cant have too many Pi’s. (other projects on the horizon)
If I ever need to make changes a NUC will be the next host choice, or would yous recommend a docker installation?

1 Like
4

I personally run HA in a podman container in a debian VM but running HAOS in a Proxmox VE VM on that NUC is a good choice too. I have one for testing/helping, I just don’t use it in production. HAOS needs more resources than just HA alone but most people enjoy the addon/app feature. I prefer having full control myself. For reference, my HA container uses 1.6G~ right now.

1 Like
5

Just wondering how much extra it would have taken to make the leap to 4Gb, (or even the recently released 3Gb model to relieve memory shortage price peaks) to postpone the inevitable memory exhaustion as you expect your Pi to do more and more as you update and add apps?

6

Nice. I will pursue this style of setup.
When I started with HA I tested with a docker image. Because my servers are in the cellar I wanted the coordinator to be placed in a more central location in the house, so i opted for a Pi installation.
Now the ZigBee mesh is established the coordinator can be located anywhere. I can move back to a docker installation.
I see some HAOS images for future use. Will tinker with these.

7

I’d recommend the official HA image like this.

8

You may run HomeAssistant with as low as 512MB RAM with zram compression on a PiZero2W, using container install on a baseline Alpine system (much lower requirements than Debian): an easy automated setup install script is described here and can be used on any platform.
So Pi4 1MB is even more comfortable ! :wink: