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Replacing a $3000/mo Heroku bill with a $55/mo server

(disco.cloud)
804 points jryio | 2 comments | 21 Oct 25 20:28 UTC | HN request time: 0s | source
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speedgoose ◴[21 Oct 25 21:12 UTC] No.45661785[source]▶
Looking at the htop screenshot, I notice the lack of swap. You may want to enable earlyoom, so your whole server doesn't go down when a service goes bananas. The Linux Kernel OOM killer is often a bit too late to trigger.

You can also enable zram to compress ram, so you can over-provision like the pros'. A lot of long-running software leaks memory that compresses pretty well.

Here is how I do it on my Hetzner bare-metal servers using Ansible: https://gist.github.com/fungiboletus/794a265cc186e79cd5eb2fe... It also works on VMs.

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shrubble ◴[21 Oct 25 22:32 UTC] No.45662569[source]▶
It's always a good idea to have a tiny amount of swap just in case. Like 1GB.
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akerl_ ◴[21 Oct 25 23:26 UTC] No.45663070[source]▶
Why?
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1. angch ◴[22 Oct 25 04:15 UTC] No.45664831[source]▶
Like a highway brake failure ramp, you have room for handling failures gentler. So services don't just get outright killed. If you monitor your swap usage, any usage of swap gives you early warning that your services require more memory already.

Gives you some time to upgrade, or tune services before it goes ka-boom.

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2. akerl_ ◴[22 Oct 25 04:22 UTC] No.45664856[source]▶
If your memory usage is creeping up, the way you'll find out that you need more memory is by monitoring memory usage via the same mechanisms you'd hypothetically use to monitor your swap usage.

If your memory usage spikes suddenly, a nominal amount of swap isn't stopping anything from getting killed; you're at best buying yourself a few seconds, so unless you spend your time just staring at the server, it'll be dead anyways.