System Recovery Boost Upgrade

What is System Recovery Boost Upgrade?

System Recovery Boost Upgrade supports activating temporary zIIPs in conjunction with a zIIP boost during an image IPL boost period or a shutdown boost period. It is a priced feature for the z15 and requires you to have purchased an annual subscription for the boost feature for your CPC and allows 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. You can bring this additional zIIP capacity online to your CPC when it is needed for recovery purposes. These zIIPs then behave just like any other physical zIIPs, in that the processors are shared across the CPC based on their LPAR weights, and additional reserved zIIPs can be brought online at the beginning of a boost due to the additional physical capacity being made available.

After the temporary capacity record expires or is deactivated, the additional zIIPs are removed from the CPC’s pool of physical processors. Any zIIP processors you want managed by z/OS as part of System Recovery Boost (that is, automatically brought on and offline) have to be available to the CPC when the boost is started. Physical processors that are made available after the boost has started are not automatically brought online by z/OS.

System Recovery Boost Upgrade is eligible for use during one or more image-level IPL or shutdown boost periods. It does not change the time limits of IPL boost periods (60 minutes) or shutdown boost periods (30 minutes). It cannot be used with recovery process boosts.

How does System Recovery Boost Upgrade work?

As an example, consider a CPC with five shared physical zIIPs and three LPARs, another with no initial zIIPs, another with three initial zIIPs and another with five initial zIIPs.

With no initial zIIPs, z/OS is not able to take advantage of zIIP boost unless the image has 1 or more reserved zIIPs defined. If there are one or more reserved zIIPs defined, during the boost period, up to five reserved zIIPs will be configured online by z/OS, and then configured offline once the boost period is over. If you have a temporary capacity record, then more zIIPs could be configured online during a boost period, up to the maximum allowed by the system definition or the physical number of zIIPs available.

With three initial zIIPs, z/OS can take advantage of zIIP boost. If one or more reserved zIIPs is defined, up to two reserved zIIPs are configured online by z/OS at the beginning of the boost period, and then configured offline once the boost period is over. If you have a temporary capacity record, then more could be configured online during a boost period, up to the maximum allowed by the activation profile or the physical number of zIIPs available.

With five initial zIIPs, z/OS is able to take advantage of zIIP boost. However, unless you have a temporary capacity record, no more zIIPs are able to be configured online by z/OS at the beginning of a boost period. If you have a temporary capacity record, then more could be configured online during a boost period, up to the maximum allowed by the activation profile or the physical number of zIIPs available.