There are three classes of boost: IPL (startup) boost, recovery process boost, and shutdown boost. Each class has different capabilities.

IPL boost is enabled by default and delivers extra processor capacity after an IPL to get you back up and running faster.

Recovery process boost provides increased short-duration processor capacity for the acceleration of sysplex recovery situations.

Planning and setup:

These recovery process boosts are enabled by default: HyperSwap, Coupling Facility data-sharing member recovery, Coupling Facility structure recovery, sysplex partitioning, and, with the IBM z16, HyperSwap configuration load. With the IBM z16, you can configure these additional recovery process boosts: SVC dumps and middleware region startups.

Shutdown boost enables a faster shutdown by delivering extra processor capacity upon indication that a shutdown is in progress.

Planning and setup:

Update your shutdown automation to automatically use the START IEASDBS system command during your shutdown process to use shutdown boost to speed up the shutdown.

There are two boost types, Speed Boost and zIIP Boost.

Speed Boost is a capability of System Recovery Boost that improves the recovery time of exploiting operating systems when running on a subcapacity CPC. If you are running on a subcapacity CPC, then while System Recovery Boost is active, z/OS will request that the CPC firmware increase the CP speed of the image to full capacity model speed for the duration of the boost. After the boost ends, the image will return to the subcapacity model speed.

Speed Boost applies to each of the three boost classes: IPL boost, recovery process boost, and shutdown boost.

Planning and setup:

Speed Boost applies only to the image being boosted; all other images not being boosted will run at subcapacity model speed.

If you’re running on a subcapacity machine, there is no reason not to run with speed boost. Any processing activity that uses CPs will benefit from Speed Boost. Use the following links to learn more:

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: IPL 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 IBM 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 IPL boost and shutdown boost.

IBM is offering a 90-day free trial for System Recovery Boost Upgrade, so that you can test out System Recovery Boost Upgrade in your own environment. The trial gives you 30 activations, each of which can be used to unlock up to 20 additional zIIP processors for up to 6 hours.

You can order the 90-day trial record using Resource Link. Resource Link will immediately stage the record for download upon ordering. Ordering requires online-buying enablement and the associated contract supplements, as well as SRB Upgrade Authorization.

You are eligible for the trial if you are a new or existing IBM z15 T01 or IBM z16 A01 customer, and if you have not already purchased the full System Recovery Boost Upgrade offering.

Use the following links to learn more:

GDPS® performance and parallelism increases the speed with which GDPS drives hardware actions, along with enhancing the speed of the underlying hardware services. The GDPS enhancements are available in GDPS 4.2 and above running on an IBM z15 or IBM z16.

GDPS takees advantage of the HyperSwap exploitation of recovery process boost.

IBM recommends reading the following GDPS manuals, which describe how to implement these RTO improvements:

• GDPS Metro Planning and Implementation Guide (ZG24-6755), section 4.7.2, SYSPLEX script statement.
• GDPS Global - GM Installation and Customization Guide (ZG24-6757), section 4.5.7, SYSPLEX script statement.
• GDPS Global - XRC Installation and Customization Guide (ZG24-6759), section 4.6.9, SYSPLEX script statement.