Space 2.2.1 theme works only with Moodle 4 and later.
- Disk space: 200MB for the Moodle code, plus as much as you need to store content. 5GB is probably a realistic minimum.
- Processor: 1GHz (min), 2GHz dual core or more recommended.
- Memory: 512MB (min), 1GB or more is recommended. 8GB plus is likely on a large production server
- Consider separate servers for the web "front ends" and the database. It is much easier to "tune"