Just as we expected, the best place for the new mainframe is to replace old mainframes, not Unix (Linux) or other non-mainframe systems. This comes from a end user/customer who admits exactly that, you can read it in this search datacenter article.

But here is the quote "Though IBM has pushed hard to present the mainframe as a consolidation target for hundreds, if not thousands, of virtual Linux servers, Handera saw the new machine as a boon to better handling more traditional mainframe applications such as DB2, WebSphere and CICS batch jobs."

So get rid of the old mainframes and migrate them to the new one. That way you can save costs. During the migration project, you may be able to take some applications off the mainframe and run it on another more open and cost effective and open system giving you more choice and options in the future.

As you move from an old mainframe you often find systems that do not need to run on there anymore, faster, newer and more cost effective Unix servers for which you can do open bids are often more efficient. So it is good to do a review now and again on how you can reduce your zOS dependence.

Remember if you look for a new mainframe, only one company can give you a price. If you want to buy a new mainframe/Unix server you have several suppliers.

Mainframe market is a monopoly, thus you will pay monopoly prices. Do not try and stay dependent on a single supplier, this is not good for business. Shame that we do not have Amdahl and Hitachi making zOS mainframes/servers anymore.

The IBM mainframe is good for running traditional MVS or z/OS apps like CICS and batch jobs that no-one can understand anymore. If you want more mainstream IT stick with UNIX mainframes.