Operating-system: How can i increase my swap file size?

[basdejong95]

HassOS release with the issue:

HassOS 4.15

Supervisor logs:

Journal logs:

Kernel logs:

Description of problem:

Hi everybody,

I am using home assistant on a RPI 4 with 1GB of ram. My swap file is only 230mb and fills up pretty fast, in the last week or so i had home assistant crashing a lot and i noticed my swap file is almost pretty full. While reading about this there are pretty clear instructions on the internet on how to increase the swap file on a standard RPI, but i cannot find it anywhere for HASSOS. Does anybody know a command or a setting i can change to increase this? I have a 128GB SD card which is A2 class so i dont mind creating a swap file of 1-2GB.

Thank you!

[agners]

Currently Home Assistant OS does not really support that use case. This is also taking a strain on your SD card as swap usually generates quite a bit of read and writes. Since we already have users which have problems with SD cards wearing out, in a lot of cases using swap on SD card does not make sense.

By default HAOS configures a part of the RAM as compressed swap storage (using zram). This helps quite a bit for boards with low memory.

That said, when you access HAOS directly (via SSH port 22222), you can create a swapfile and enable it as swap, but the swap will not be automatically re-enabled after a reboot:

# fallocate -l 4G /mnt/data/test.swap
# mkswap /mnt/data/test.swap
# chmod 0600 /mnt/data/test.swap
# swapon /mnt/data/test.swap

[bachy]

hi,
my hassos lives in a rpi3b+ with a 120Go ssd connected via usb
i moved the data partition on the ssd
my memory is at 80% and swap at 100%
i don't have so much devices and entities (357) (discovered HA 2 weeks ago)
using rfxtrx, z-wave, zigbee
top says that homeassistant is consuming 31%, mysqld 16%, systemd-journald 5%, node-red 5% and supervisor 2.5%
i succesfully added a 4G swap file as describe above, i'll see if it prevent my instance to freeze
is there any way to make it permanent ? i mean active on reboot
i saw that there is nothing on /etc/fstab
i know nothing about buildroot
thanks

[Jpsy]

Do yourself a favor and switch over to an RPi4 with more than 1GB of RAM. You will only waste time with you trials on 1GB. The difference that more RAM makes is overwhelming.

[bachy]

Yes i know, unfortunatly my z-stick gen5 is not compatible with rpi4 and i'm lazzy to rebuild all my zwave mesh (qubinos wire pilote on the wall behind heaters)

[frenck]

Do yourself a favor and switch over to an RPi4 with more than 1GB of RAM.

Better yet, grab an ODROID N2 or N2+

[basdejong95]

Do yourself a favor and switch over to an RPi4 with more than 1GB of RAM. You will only waste time with you trials on 1GB. The difference that more RAM makes is overwhelming.

Home assistant says on the getting started website that 1GB ram should work... And it would work if my swap file could be bigger. However there is no way to permanently change this, only the commands from @agners are a manual solution for now?

[basdejong95]

this is my swap file within 1 day of rebooting

[JZ-SmartThings]

@agners that standard solution doesn't seem to work... see the error which suggests that BusyBox and not the full version of swapon is what HassOS seems to be using. Error you get is invalid argument for swapon. FYI, swapon -a ran fine but did not use the newly created swap file either. With my SSD plugged into the RPI3B+, it'd be nice to be able to control the default swap behavior in HassOS.

[QbaF]

for me

[capstan1]

Currently Home Assistant OS does not really support that use case. This is also taking a strain on your SD card as swap usually generates quite a bit of read and writes. Since we already have users which have problems with SD cards wearing out, in a lot of cases using swap on SD card does not make sense.

By default HAOS configures a part of the RAM as compressed swap storage (using zram). This helps quite a bit for boards with low memory.

That said, when you access HAOS directly (via SSH port 22222), you can create a swapfile and enable it as swap, but the swap will not be automatically re-enabled after a reboot:

# fallocate -l 4G /mnt/data/test.swap
# mkswap /mnt/data/test.swap
# chmod 0600 /mnt/data/test.swap
# swapon /mnt/data/test.swap

This works like a treat! On my ssd that should be perfect to prevent filling up the ram completely.

Any idea on how to make this persistent?

[dpjrodrigues]

I do understand what @agners say and I do agree that if you use an SD card increasing the swap is not great but if you use an SSD then shouldn't be a problem.

Since few months ago my pi3b+ is getting very slow and HA ends up not responding. Restart fixes it and then after 1 week or so again the same thing.
I’ve added few checks and realized that it may be related with memory… once swap hits close to 100% and RAM 90% this happens.
I do not have that many addons and it was working ok before… there are few discussion on potential memory leaks but anyway it is not the purpose of this topic.

I’m running an SSD with my pi so raising the swap size could reduce or even solve some of these issues. The default setting is just 25% of the real device memory (in this case 256Mb) and I think that it is probably having in SDcards in mind (and not SSD)

I’ve managed to change it using the commands below and so far so good… the problem is that this is not persistent (and after restart goes back to original swap size). As far as I understood I would need to change the /usr/libexec/hassos-zram or /usr/lib/systemd/system/zram-swap.service but the filesystem is read-only. Is there any other way to do this?

swapoff /dev/zram0
zramctl --reset /dev/zram0
zramctl --find --size 1024M
mkswap /dev/zram0
swapon /dev/zram0

[dpjrodrigues]

Just a quick update to mention that increasing the swap size is working well so far. Now the RAM is stable 65% - 70% and the swap is between 30% - 35% so not that much from the forced 25% (the problem is that this configuration is lost when restarted)