This week alone, three people have asked me about Outworldz DreamGrid. Simply put, it's a powerful software developed by Ferd Frederix (Fred Beckhusen) that makes it incredibly easy for anyone to run their own virtual grid. If you're curious to learn more, you can check it out here: https://outworldz.com/Outworldz_installer/Grid/ https://www.outworldz.com/
I once ran opensimulator on slitaz linux, on a pIII 900 mhz with 512 mb ram. 1 region. LOL. It was actually not slow at all. But I couldn't have more than 1 visitor.
Dreamworld started as a Perl script that would build a working grid on a Pi. In 2010, in 2 GB RAM on a microSD card. Runs better now on a Pi4, with 8 GB RAM, and they finally fixed the floats issue in physics. Still a toy, and very limited.