Hi Shifali,
As rightly pointed out by mohan, Sizing will depend upon the no.of repository, and no. of records and also depends on the landscape of your poject i.e with how many system MDM is interacting.
Addition, to this the language plays a major role in repository sizing as each language will act as one layer upon another. So, Advise to use only the required language for your repository.
Below are some links related to the hardware requirements:-
https://scn.sap.com/message/6172294
Hope it helps.
Thanks!!
Regards
Prateek