Occasionally I get very high CPU load. Generally the operation is very smooth but then there are those burst of full CPU load. While that is happening, the forum give 502 errors or is VERY slow. I have a Hetzner server with 3 vCPUs and 4 GB of RAM. [Bildschirmfoto 2025-10-11 um 20.43.18] Anyone has an idea what could cause this?

A periodic process is running. Do you have swap? You’re running out of memory. I would add 2 to 4gb of swap.

I had to wait to catch an high CPU event. I ran htop and took some screenshots (I never used it so I don’t know what I’m looking at). [Bildschirmfoto 2025-10-13 um 20.42.31] [Bildschirmfoto 2025-10-13 um 20.43.30] [Bildschirmfoto 2025-10-13 um 20.43.55] [Bildschirmfoto 2025-10-13 um 20.43.02] [Bildschirmfoto 2025-10-13 um 20.43.09] [Bildschirmfoto 2025-10-13 um 20.42.56] [Bildschirmfoto 2025-10-13 um 20.42.51] [Bildschirmfoto 2025-10-13 um 20.42.44]

[image] pfaffman: Do you have swap? You’re running out of memory. I would add 2 to 4gb of swap. This is the first thing to do.

No swap is not a good look here, you are dangerously close to major issues.

@GeorgSeifert were you able to resolve your issue? If adding swap is the fix, please mark @pfaffman’s post as the solution. It’s the button on the post menu that looks like a square with a checkmark in it.

I tried a different sever that has more RAM but slower CPU and is cheaper. I’ll monitor this for a few days.

Did you add swap? That is essential.

I thought double the physical RAM should do for now. The Discourse page says that a server with 1-2 MB RAM is enough to run it. So I thought I’m kind of save with 4 MB? Now it has 8. I’m not sure if our forum has a lot trafic (I just check the Reports and it says 15 logged in and 1000 not logged in users).

[image] GeorgSeifert: The Discourse page says that a server with 1-2 MB RAM is enough to run it It is enough — without plugins and few other things, like users and an active admin/moderator. That is absolut minimum and even forum itself can work, rebuilding will fail. We have here quite few topics about that question and one kind consensus is 2 MB is enought for small forums, if there is swap too.

@pfaffman refresh my memory.. does the ./discourse-setup command not create the swap file automatically? @GeorgSeifert have you followed the official install instructions to set up your site? If not it is goin to be hard for us to support you here. As everyone is telling you, you need to have a swap file, no matter how much memory you have, otherwise you will run into difficulties.

Occasionally very high CPU load

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merefield (Robert) October 25, 2025, 1:41pm 23

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Occasionally very high CPU load

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