I worked on building Debian packages en masse to Nexenta back in the day. I really loved zones+zfs+dtrace which were incredibly well integrated together. All of those technologies live on in some form but none of them are nearly as well integrated as they were on Solaris 10 or OpenSolaris.

My favorite video of the time is still a guy screaming into a rack of spinning rust and watching read latencies spike on the drives nearest his mouth.