←back to thread

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
Show context
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.

replies(15): >>45661833 #>>45662183 #>>45662569 #>>45662628 #>>45662841 #>>45662895 #>>45663091 #>>45664508 #>>45665044 #>>45665086 #>>45665226 #>>45666389 #>>45666833 #>>45673327 #>>45677907 #
levkk ◴[21 Oct 25 21:51 UTC] No.45662183[source]▶
Yeah, no way. As soon as you hit swap, _most_ apps are going to have a bad, bad time. This is well known, so much so that all EC2 instances in AWS disable it by default. Sure, they want to sell you more RAM, but it's also just true that swap doesn't work for today's expectations.

Maybe back in the 90s, it was okay to wait 2-3 seconds for a button click, but today we just assume the thing is dead and reboot.

replies(16): >>45662314 #>>45662349 #>>45662398 #>>45662411 #>>45662419 #>>45662472 #>>45662588 #>>45663055 #>>45663460 #>>45664054 #>>45664170 #>>45664389 #>>45664461 #>>45666199 #>>45667250 #>>45668533 #
zymhan ◴[21 Oct 25 22:34 UTC] No.45662588[source]▶
Where on earth did you get this misconception?
replies(1): >>45662616 #
commandersaki ◴[21 Oct 25 22:36 UTC] No.45662616[source]▶
Lived experience? With swap system stays up but is unresponsive, without it is either responsive due to oom kill or completely down.
replies(1): >>45662754 #
1. GuinansEyebrows ◴[21 Oct 25 22:53 UTC] No.45662754{3}[source]▶
in either case, what do you do? if you can't reach a box and it's otherwise safe to do so, you just reboot it. so is it just a matter of which situation occurs more often?
replies(1): >>45664321 #
2. commandersaki ◴[22 Oct 25 02:36 UTC] No.45664321[source]▶
The thing is you can survive memory exhaustion if the oom killer can do its job, which it can't many times when there's swap. I guess the topmost response to this thread talks about an earlyoom tool that might alleivate this, but I've never used it, and I don't find swap helpful anyway so there's no need for me to go down this route.