If two years and eight months exist before the expiration date at the time of the order, the  expiration date can be extended by no more than two years. One test activation is provided for  each CBU year that is added to the CBU entitlement record. FC 6805 allows for ordering more tests in increments of one. The maximum number of tests  that is allowed is 15 for each FC 6818. The processors that can be activated by CBU come from the available unassigned PUs on  any installed processor drawer. The maximum number of CBU features that can be  ordered  is  190. The number of features that can be  activated  is limited by the number of unused PUs on  the system; for example: The ordering system allows for over-configuration in the order. You can order up to 190 CBU  features, regardless of the current configuration. However, at activation, only the capacity that  is installed can be activated. At activation, you can decide to activate only a subset of the  CBU features that are ordered for the system. Subcapacity makes a difference in the way that the CBU features are completed. On the  full-capacity models, the CBU features indicate the amount of extra capacity that is needed. If  the amount of necessary CBU capacity is equal to four CPs, the CBU configuration is four  CBU CPs. The subcapacity models feature multiple capacity settings of 4 xx , 5 yy , or 6 yy . The standard  models use the capacity setting 7 nn . To change the capacity setting, the number of CBU CPs  must be equal to or greater than the number of CPs in the base configuration.  For example, if the base configuration is a two-way 402, providing a CBU configuration of a  four-way of the same capacity setting requires two CBU feature codes. If the required CBU  capacity changes the capacity setting of the CPs, going from model capacity identifier 402 to  a CBU configuration of a four-way 504 requires four CBU feature codes with a capacity setting  of 5 yy .  If the capacity setting of the CPs is changed, more CBU features are required, not more  physical PUs. Therefore, your CBU contract requires more CBU features when the capacity  setting of the CPs is changed.  CBU can add CPs through LICCC only, and the z15 server must have the correct number of  installed processor drawers to allow the required upgrade. CBU can change the model  capacity identifier to a  higher value than the base setting (4 xx , 5 yy , or 6 yy ), but the CBU  feature cannot  decrease  the capacity setting.  A CBU contract must be in place before the special code that enables this capability can be  installed on the system. CBU features can be added to a z15 server nondisruptively. For each  system enabled for CBU, the authorization to use CBU is available for 1 - 5 years. The alternative configuration is activated  temporarily , and provides more capacity than the  system’s original,  permanent configuration. At activation time, determine the capacity that you  require for that situation. You can decide to activate only a subset of the capacity that is  specified in the CBU contract. Chapter 8. System upgrades  371 GLYPH<SM590000> A z15 Max 34 with Capacity Model Identifier 401 can activate up to 34 CBU features.  These CBU features can be used to change the capacity setting of the CPs, and to  activate unused PUs. GLYPH<SM590000> A z15 Max 71 with 15 CPs, 4 IFLs, and 1 ICF has 51 unused PUs available. It can  activate up to 51 CBU features.