And not overcommitting memory.

But Illumos is a real modern viable option over Linux (and *racle Solaris) for server hardware.

On the onboarding thing, Oracle Cloud didn't offer Solaris as an OS option last time I checked. And, of course, they never offered SPARC because abandoning it was one of the first moves. IIRC, IBM Cloud also doesn't offer Linux on POWER (but they do offer AIX and IBMi, as well as z/OS - and Linux - on s390x). Not that long ago I tried to convince VMSI to make a deal with cloud providers and allow OpenVMS to be as easy as any other OS on amd64.