I would ask a few key users to run through all of their objects in the environment: check forms, grids, reports, etc., to make sure they all exist and behave correctly. I would then add a period of data and confirm the whole end to end process works and that performance is as expected. 11.2 performance should be the same as 126.96.36.199, all other things being equal.
True - that is a good start for sure.
Currently we have links to check if workspace is up, open forms and grid and so on.
What would be a good check for DRM,. FDMEE and Web studio?
What you are asking for is basically regression testing. You can do it informally, precisely as Chris described - ask a couple of key users to play around. Your alternative is to formalize it, and sit down with people to devise a couple of end-to-end- scenarios, ask them what task the perform or reports they run, and document that.
Without knowing what applications are in use, how you configured them, and what the standard processes are, it is really hard to answer your question other then: "try to execute key tasks and run key reports"
This is something that is to be done after the server or services are restarted
Components to check in HFM 11.2
1) HFM application
3) Reports / Web studio
I echo what Chris and others have mentioned. I will just add that if you have the benefit of owning the Accelatis Suite you can automate this process by creating simulation packages that open artifacts, run consolidations/ calculations, etc. You can automate the service restarts and simulations and have it notify you if any errors come out of the simulations.
Thanks for the suggestion - something like Accelatis would be useful.