Joined: 06 Jun 2008 Posts: 8344 Location: Dubuque, Iowa, USA
The recommendations are recommendations, not requirements. If you're using Java with your CICS regions, the 2 GB may be more a mandatory requirement than a recommendation but without Java you should be able to start somewhere close to your current value -- although you may have to go up some due to new functionality in CICS.
z/OS on the z10 EC machines support a minimum of 16 GB to a maximum of 1520 GB for the machine; I believe pretty much any of the z machines support 8 GB of memory. You may need to contact your site support group to verify the memory allocated to your LPAR is at least 2 GB before you start the CICS region with 2 GB, but most recent machines are set up with several GB per LPAR anyway.