Automatic Activation of System Recovery Boost Upon System Shutdown

IBM Z System Recovery Boost is a new feature that is available with the IBM z15 (z15). It can temporarily leverage additional processor capacity during IPL and shutdown times to reduce the overall downtime due to recovery or maintenance activities. This new function requires z/OS V2.3 and OA57849 or z/OS V2.4. At IPL time, a system can automatically participate in the boost unless the BOOST system parameter in IEASYSxx is set to NONE. At shutdown time, the operator has to explicitly activate the boost by starting the new started procedure IEASDBS that is provided by z/OS. For further information about System Recovery Boost, see z/OS documentation.

SA z/OS can automatically activate System Recovery Boost upon shutdown of a system. SA z/OS checks whether the operational prerequisites are met and if so starts the started procedure IEASDBS. Specifically, SA z/OS checks whether it runs on z/OS V2.3 or higher, whether boost is enabled in IEASYSxx and that the system is not already operating in boost mode. IEASDBS is started only when all conditions are met. SA z/OS does not check whether it runs on a z15.

If System Recovery Boost should not be activated automatically upon system shutdown, even if enabled by the operating system, the administrator can pass the new INGREQ parameter BOOST=NO with the INGREQ ALL request. To permanently disable System Recovery Boost during shutdown of a system, the administrator can set the global variable INGREQ_BOOST to NO.

When a system is shut down via GDPS, SA z/OS also automatically activates System Recovery Boost when the operational prerequisites are met. To avoid automatic activation of System Recovery Boost, the administrator can set the advanced automation option AOF_AAO_SHUTDOWN_BOOST to NO.

IEASDBS activates System Recovery Boost only once. If it has been started manually before an operator requests a shutdown via SA z/OS, SA z/OS will detect it and not start the procedure again. If the procedure is started manually after an operator requests a shutdown via z/OS and z/OS has already started it automatically, messages on the system console indicate that an error occurred but no further action is required.