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

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.

It's always a good idea to have a tiny amount of swap just in case. Like 1GB.

Why?

Because some portion of the RAM used by your daemons isn't actually being accessed, and using that RAM to store file cache is actually a better use than storing idle memory. The old rule about "as much swap as main memory" definitely doesn't hold any more, but a few GB to store unneeded wired memory to dedicate more room to file cache is still useful.

As a small example from a default Ubuntu installation, "unattended-upgrades" is holding 22MB of RSS, and will not impact system performance at all if it spends next week swapped out. Bigger examples can be found in monolithic services where you don't use some of the features but still have to wire them into RAM. You can page those inactive sections of the individual process into swap, and never notice.

If my swap is on my disk, what good is storing file cache there, next to the files?