The Personas 3 configuration guide contains all the information you need. At least two profile parameters need to changed to ensure that the Personas 3 health check passes:
Change profile parameter em/global_area_MB to 1GB:
I will run Personas 3 on a demo system, having as only user me. I do not have to change the default value therefore. If you want to or have to change the value, you can do so in the instance profile, under extended maintenance.
Change profile parameter ztta/diag_area to 2º MB.
Save and activate profile.
Restart NW ABAP to make the new values effective.