If you are:
- running a recent 7.4x kernel (which you should since it is a pre-requisite for SAP Screen Personas 3.0 SP 02)
- you are using zero administration memory management (which is the default for most platforms)
The most important and relevant instance profile parameters for SAP Screen Personas 3.0 SP 02 are:
As provided by SAP all 3 parameters are related in the following way:
em/global_area_MB = (min($(em/initial_size_MB) * 0.05, 32000))
em/initial_size_MB = (min(512000, $(PHYS_MEMSIZE) * 0.7))
Now knowing that the recommendation and the criteria to pass the Personas Health Check is to have around 1 GB of global area memory, this translates to:
em/global_area_MB = 1024
em/initial_size_MB = 20480
PHYS_MEMSIZE = 29257
So here is the catch. Unless your SAP server has 30 GB of physical RAM dedicated to the AS ABAP instance in question, you won’t be able to meet the pre-requisites and the Personas Health Check will show up as red.
Now you may want to argue that you can change the value of em/global_area_MB to not be based on em/initial_size_MB. Sure you can do that but are you sure you want to do that? Not to follow years and years of experience SAP has with automatically tuning the instance to get the optimal performance? That is assuming you actually understand the implications of deviating from the default values.
Nowhere in the SAP Screen Personas 3.0 SP 02 documentation, notes, Wiki, etc. is this real life pre-requisite mentioned so you should be aware of it. For some it may not be an issue; heck, RAM is cheap these day, right? – But for others it might be, like in a virtualized environment with tens or hundreds of SAP instances with limited physical memory available on the host.