ERPNext should work using the setup you describe. I don’t think anyone has tried this yet?
ERPNext would not be the limiting factor here as what you require is handled by the OS and DB.
The setup would be fairly involved and would require advanced Ubuntu server and DB management skills.
I understand your interest in separating your data from the Host OS hardware but as you have 600GB of mirrored raid I would ask if it is just not simpler to run the OS and DB on the same raided partition? The OS weighs in at about 1GB leaving 599GB of mirrored raid for your DB.
What is EGTE?