It was the future OS most fails to understand. The ZFS/IPS integration was the first modern step aside of declarative distros. A thing 99% of people still fails to understand refusing the concept of storage system/package system/installer interdependence.
Zones, DTrace was the rest.
Do you have any recommended references to understand that concept and how it plays out in Solaris?
I find myself in the middle of what I imagine are similar design challenges in software packaging, storage, integration, and deployment.
I submit that the problem was Solaris 9 just being massively overtaken by desktop Linux in every way - easier to install, faster, simpler to patch, better GUI, more software available. Solaris 10 was too little too late; it already had to compete with mature Linux offerings that had a greater mindshare, and the excellent features like Zones were too far ahead of their time (and lacked the centralized store of downloadable Zone-prepackaged apps that is really the reason for Docker's success).
Purity doesn't matter in practice - especially in a world where OS installations are increasingly ephemeral and ideally immutable.
I always hear DTrace is awesome, but have never used it. And seem to have gotten by just fine... what am I actually missing?
ZFS, on the other hand, was so good that it has outlived Solaris itself and is at the core of e.g. TrueNAS as a commercial product.