Turning on System Recovery Boost

System Recovery Boost is activated by default, and can be controlled via the BOOST= parameter in your IEASYSxx parmlib member. The default, BOOST=SYSTEM, means that z/OS will take advantage of whatever boost(s) are available to it, given the system configuration. BOOST=ZIIP will only allow for zIIP Boosting, while BOOST=SPEED will only allow for Speed Boost. BOOST=NONE will disable all types of boosting. (See below for more information on the BOOST parameter.)

The system command, DISPLAY IPLINFO,BOOST can be used to view the value of the BOOST system parameter. The system command, Start of changeDISPLAY IPLINFO,BOOST,STATE can be used to display information about the boostsEnd of change. There are also indicators on the HMC that can tell you if an image is currently boosting or not; the Image Detail panel will tell you if an image is boosting, and there’s a new column in the Systems Management list and Custom Groups list that will indicate if a boost is active, but not which type(s).

System Recovery Boost can be used twice during an IPL, for each image: once during IPL, and once while shutting down the system.

Start of changeStartup Boost will automatically be activated during IPL, and last for 1 hour, but you start Shutdown Boost by using the START IEASDBS command. For more information on each of these topics, see Startup Boost, and Shutdown Boost.End of change

BOOST

BOOST={SYSTEM| ZIIP | SPEED | NO[NE]}
Two boosts are possible: zIIP boost and speed boost. These boosts are available when running z/OS® on a machine with IBM z15™ capabilities only.
The zIIP boost configures online zIIPs in the standby state in accordance with the zIIP configuration of the LPARs. The zIIP boost will "blur" work between standard CPs and zIIPs. (That is, work that is normally eligible only for a standard CP may be run on a zIIP.) zIIP boost only applies to an LPAR that, at the time of boost activation, meets all of the following criteria:
  • Has at least one online or standby zIIP
  • Is not a dedicated partition
  • Is running with HIPERDISPATCH=YES

In order for zIIPs to be configured online during boost processing, the zIIPs must be defined to the LPAR. They may be defined before IPL or they may be dynamically added to the configuration after IPL, depending on the LOADxx DYNCPADD parameter value in effect. zIIPs dynamically added after IPL do not apply to IPL boost but could be used by shutdown boost.

The speed boost makes a sub-capacity standard CP run at the speed of a (full-speed) zIIP. Speed boost only applies to an LPAR that, at the time of boost activation, does not have its standard CP(s) already running at the (full-capacity) speed of a zIIP.

Start of changeBoost start is evaluated at three points:
  • At IPL
  • At the requested start of a recovery process boost
  • At shutdown, as identified by using the command START IEASDBS
End of change
SYSTEM
Apply system rules. If the machine does not support boosts, treat as NONE. If the system does support boosts, activate all boosts that the machine supports.
ZIIP
Activate only the zIIP boost. Do not activate the other (speed) boost.
SPEED
Activate only the speed boost. Do not activate the other (zIIP) boost.
NONE | NO
Do not activate either of the boosts.

The specification may be displayed using the DISPLAY IPLINFO,BOOST command.

Value range: Not applicable
Default: BOOST=SYSTEM
Associated parmlib member: None