How much disk space for running HomeAssistant OS?

Hello. I’m about to purchase an Odroid N2+ with eMMC module to run Home Assistant OS, but I’m wondering what size I should go for. Could someone please advise how much disk space would be required to run HAOS?

As a complement of information, I’ve got a separate NAS with my multimedia files on it and plenty of spare space. I could eventually have the recorder database on the NAS, but I wonder how much this might affect performance.

Thanks for your suggestions.

At the moment my install uses a total of 19,5 GB, the database recorder is managed to stay stable size.

This will likely depends on how much time you want to keep in the database & how much entities you will have & how much these entities will update their state. So basically there is no easy advice !

I can tell you my own setup :
My HAOS is using 7Gb without database. My Database is around 250Mb with 3 days retention and 513 entities.

Having the database splitted from the install should not affect too much performances. Just keep in mind it will prevent your NAS disks to go to “sleep” as the database will always have to write.

Some very good points here, thanks very much.

Is it possible to configure the retention policy at the entity level? For instance, I would have like to keep energy use and heating data for 12 to 18 months, so that I can compare year on year, and observer variation based on seasons (UK). But obviously, no need to keep 12 months of history for a light switch!

No that is not possible. However some energy data is stored as LTS (long term statistics) and is not purged. You can do this for your heating sensors too by adding the state_class: measurement attribute to them.

I would add that the HA database is quite good but probably not made to store so much history and will be quite difficult to use to compare year to year datas. Better use a real time series database like influxDB. You can run it as addon with grafana as visualisation helper. And in that case, you can select entity based what you want to keep in influxDB.
For example in my case I keep 3 years of detailled datas in my influxDB but only few sensors :smiley: Switches, lights… are not in my influxdb and I only have them 3 days in my HA database.

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And if you want to learn how to set up InfluxDB and Grafana in 15 minutes watch this:

The only thing I would add is to use includes in the Home Assistant InfluxDB integration to only include sensors you want to store long term data for.

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why does the disk take up so much space (46G), but the full backup is only 1.6G ?

Data compression is a thing. (databases with lots of repeated data compress incredibly well)
Many of the files on disk are transient and don’t need to be backed up…

Pick one. Or both. Could be a bunch of things but those two are the biggest ones. Sounds like TAR is doing a great job.

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