I just did a fresh install of Debian 10 and it is still the default. I understand that they want to support hibernation out of the box but it creates gigantic swaps for a feature that I believe is rarely used, nowadays sleep is good enough and reboots are super fast.

It would be great if the installer optionally asked how much swap to allocate without having to do the full partitioning manually.

Interestingly enough the debian installer freaks the fuck out if you have more ram than disk and choose the auto-partition option. We've run into this a few times with servers that have 512gb ram and a 120gb ssd installed. The installer doesn't seem to recognize this and try to set some sort of sane swap amount, instead it gives you some cryptic error messages about a bad disk and hangs.

You mention time to react. How do you get notified that memory usage is getting out of hand before the system is actually unusable?

Depends on the service its running really.

I'd assume that you'd have key metrics plotted in grafana, so its case of following up/alerting on that

In previous cases, It was fairly simple, an alert was fired because the queue size ballooned. Looking at the machine stats we saw that all the ram cache had been ejected just at the same time performance started to drop.

Either way, its pretty trivial to put an alert on a stat in grafana.

however, your mileage may vary.