I am setting up a Mac Mini with 2 500Gb SSDs and want to be able to dual boot into High Sierra and Catalina and future macOSs.
I initially copied an another HS SSD that had been incrementaly upgraded from 2 OSs ago onto 1 SSD, and did a fresh install of Catalina on the 2nd SSD and transferred files from the first SSD via the Mac transfer. All worked fine but I realised that this isn’t optimal with 2 installations that will get out of sync with App updates etc.
So I was exploring the option of installing both OSs in their own Volumes on the same SSD that would share the same Data volume.
However, when I examine the Catalina SSD I see a Volume with the Catalina installation (~10Gb) and the rest of that SSD is a data volume. If I look at the High Sierra SSD, there is no Volume for the OS and just one Volume for everything - so OS and data are in 1 volume…
So, my question is, can HighSierra be installed in a separate Volume that will be able to share the same data Volume as another APFS macOS?