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Comment by jauntywundrkind | Hacker News Reader

Why this and not Meta's oomd?

Or systemd's systemd-oomd https://github.com/systemd/systemd/pull/15206

The answer for both of those is "if you're unfortunate enough to be running a 2.6 kernel linux server from 2005, then you can't use cgroupsv2 and thus can't use oomd or systemd-oomd".

That is the only thing earlyoom is good for at this point I think, is old systems without cgroupsv2

Actually no there are other reasons. Meta oomd requires you to have swap enabled, which makes it a non-starter for us. systemd-oomd has its own set of drawbacks. We evaluated all options at length and earlyoom came out as the clear winner for our usecase.

Why weren't you using swap?

I'm not the parent. But in the last 5 or 8 years, Linux swap has mostly been useless to me. I run a desktop with 16GB ram, have swappiness set to 0, and even when using maybe 5GB or 7GB for running programs, it wants to swap out all kinds of stuff. When I switch to another running program I have to wait for it to get taken out of swap. But I was using that running program just a while ago, why do I have to wait?

And it doesn't help in thrashing in Linux, it does it anyway.

In defence of swap: common misconceptions[0]

[0] https://chrisdown.name/2018/01/02/in-defence-of-swap.html

No misconceptions here ;)

Still the question is open, what does swap do for me in 2023? I only see disadvantages.

For our usecase (Ceph), if one server starts swapping, it completely kills the entire cluster performance. Killing the service (with earlyoom) is preferable in most circumstances.

I spent a few days trying to configure systemd-oomd to work with my machine but I kept getting hangs when running out of memory. earlyoom is a lot simpler and thus more reliable. It only took ~5 minutes to install and test to make sure it worked and I've never had a hang since then.

Or Android’s lmkd?

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