If your system has z Integrated Information Processors (zIIPs), then zIIP boost can improve z/OS recovery time, assuming zIIP capacity is available to the image.
z/OS is the only operating system that can exploit the zIIP boost capability, as it’s the only OS that can natively exploit zIIPs. While zIIP Boost is active, z/OS will make non-zIIP eligible work zIIP eligible, thus allowing most work to run on zIIPs if there isn’t sufficient CP capacity available. This provides additional capacity and parallelism to accelerate processing during the boost periods. IBM refersto this as blurring the CPs and zIIPs together.
zIIP boost applies to each of the following boost classes: Startup boost, Recovery Process boost, and Shutdown boost.
Learn more about zIIP boost
Planning and setup
There are variations of zIIP boost, depending on how the CPC is configured, as well as the priced System Recovery Boost upgrade offering that will allow you to take additional advantage of zIIP boost.
The most basic type of zIIP boost is when you have defined Initial zIIPs, and no Reserved zIIPs that are backed by real processors. In this case, the zIIP blurring will happen for the duration of the boost on your defined, entitled zIIPs and at the end of the boost period. Normally, non-zIIP eligible work will stop running on zIIPs.
zIIP Boost with Reserved zIIPs
This is the case when you have some zIIPs that are defined as reserved, and some number of those can be backed by physical zIIPs. Those reserved zIIPs that can be backed by physical zIIPs will be brought online by the system at the beginning of the boost period, and then taken offline when the boost period is over.
System Recovery Boost upgrade
This is a priced feature for the z15 that requires you to have purchased an annual subscription for the Boost feature for your CPC that will allow you to bring up to 20 additional physical zIIPs online to the CPC for the duration of the capacity record activation, limited by the number of unused “dark core” processors you have in your CPC. System Recovery Boost upgrade can be used with Startup boost and Shutdown boost. Ordering System Recovery Boost upgrade requires three z15 hardware feature codes:
FC 9930 - SRB Upgrade Authorization | Drives necessary contracts required to enable the ordering of System Recovery Boost upgrade.
FC 6802 - SRB Upgrade Record | Enables temporary activation of additional physical zIIP processors to be used in conjunction with the base functionality.
FC 6799 - SRB Upgrade Years Ordered | Records how many subscription years you purchase for System Recovery Boost upgrade, with each feature code purchase equating to a one-year subscription.