When the emergency is over (or the CBU test is complete)  the system must be returned to its  original configuration. The CBU features can be deactivated at any time before the expiration  date. Failure to deactivate the CBU feature before the expiration date can cause the system to  downgrade resources gracefully to the original configuration. The system does not deactivate  dedicated engines  or the last of in-use shared engines. Planning:  CBU for processors provides a concurrent upgrade. This upgrade can result in  more enabled processors  changed capacity settings that are available to a system  configuration  or both. You can activate a subset of the CBU features that are ordered for  the system. Therefore  more planning and tasks are required for  nondisruptive logical  upgrades. For more information  see “Guidelines to avoid disruptive upgrades” on  page 360. For more information  see the  IBM Z Capacity on Demand User’s Guide   SC28-6846.  The activation and deactivation of the CBU function is your responsibility and does not require  the onsite presence of IBM SSRs. The CBU function is activated or deactivated concurrently  from the HMC by using the API. On the SE  CBU is activated by using the Perform Model  Conversion task or through the API. The API enables task automation. CBU is activated from the SE by using the HMC and SSO to the SE  by using the Perform  Model Conversion task  or through automation by using the API on the SE or the HMC.  During a real disaster  use the Activate CBU option to activate the 90-day period.  After CBU activation  the z14 server can have more capacity  more active PUs  or both. The  extra resources go into the resource pools and are available to the LPARs. If the LPARs must  increase their share of the resources  the LPAR weight can be changed or the number of  logical processors can be concurrently increased by configuring reserved processors online.  The operating system must concurrently configure more processors online. If necessary   more LPARs can be created to use the newly added capacity. To deactivate the CBU  the extra resources must be released from the LPARs by the  operating systems. In some cases  this process is a matter of varying the resources offline. In  other cases  it can mean shutting down operating systems or deactivating LPARs. After the  resources are released  the same facility on the HMC/SE is used to turn off CBU. To  deactivate CBU  select the  Undo temporary upgrade  option from the Perform Model  Conversion task on the SE. Test CBUs are provided as part of the CBU contract. CBU is activated from the SE by using  the Perform Model Conversion task. Select the test option to start a 10-day test period. A  standard contract allows one test per CBU year. However  you can order more tests in  increments of one up to a maximum of 15 for each CBU order.  354  IBM z14 (3906) Technical Guide CBU testing CBU deactivation Image upgrades CBU activation 8.7.2 CBU activation and deactivation