8860ch02.fm Draft Document for Review September 23, 2019 1:36 am 2.1 Scenarios 2.1.1 Scenario 1: Upgrading an existing IBM Z server to a z15 2.1.2 Scenario 2: Installing a new z15 server 2.1.3 Differences in planning for the two scenarios Throughout this book, we use two distinct scenarios by which we explain the tasks and  procedures involved to successfully install and configure a z15 server. This scenario assumes that an existing IBM Z environment where the existing IBM Z server is  upgraded by using a miscellaneous equipment specifications (MES) to a z15. The scenario  includes a planned outage period for the time of the physical upgrade of the machine. The  software environments that are supported by this machine will not be available during this  period. The serial number of the machine will remain the same after the upgrade. This scenario assumes that a new z15 is installed in an existing mainframe environment. The  z15 machine will be physically installed along with an existing IBM Z machine. After the  installation of the z15 has been successfully completed and the system has been handed  over by the IBM service representative, the software environment on the machine to be  replaced must be stopped and recabling actions must be performed.  When recabling is complete, post installation activities must be performed and the software  environment can be brought back online on the new system (z15). An outage has still to be  planned for this scenario, and a new serial number must be considered, so software keys for  the new system must be available. In the first scenario, the physical platform identity to be configured remains the same. No  hardware configuration files must be physically migrated to another platform. The machine  serial number remains the same after the upgrade, so no changes to the software licenses  are required. In the second scenario, the physical platform to be configured changes. Hardware  configuration files must be prepared on the existing machine, and must be migrated (moved)  to the new z15 server together with the attached cabling. The serial number changes with the  activation of the z15 machine, which means that planning and preparing for software license  changes must be considered. In both scenarios, we assume that bringing up the existing features and functions has highest  priority. Adding new features and functions (new functionality) acquired with the system  upgrade or installed in the new z15 have a lower priority. The elapsed time of the planned  outage can vary significantly, depending on the approach chosen in either scenario. Chapter 2. Planning considerations for CPC in PR/SM mode  9