[CoolCold]

+1 from me for

> With swap enabled, it is very, very, VERY common for the system to become completely unresponsive - no magic-sysrq, no ctrl-alt-f2 to login as root, no ssh'ing in ...

It's usually enough to have couple of times when you need to get into distant DC / wait for some IPMI connected for couple of hours, to learn "let it fail fast and gimme ssh back" on practice vs theory on "you should have swap on"

[tsimionescu]

Conversely, having critical processes get OOMKilled in critical sections can teach you the lesson that it's virtually impossible to write robust software with the assumption that any process can die at any instruction because the kernel thought it's not that important. OOM errors can be handled; SIGKILL can't.