Booting a Sun in the 90s took so long that we had the janitor go and power up the CAD lab half an hour before anyone got to the office. Whatever you are nostalgic for wasn’t a Sun.
Our Sun lab ran on SunOS 4.1.1. Its NFS implementation was so unstable we'd get perhaps an hour and a half of use at a stretch before the file server would reboot... on an 8 machine network.
When I was student, we had around 80 machines without local disk. It was working fine. They added local disks the year after with a sensible gain of performance. I loved this machine.