IBM z13s Technical Manual page 374

The processors that can be activated by CBU come from the available unassigned PUs on
ordered
any CPC drawer. The maximum number of CBU features that can be is 20. The
activated
number of features that can be is limited by the number of unused PUs on the
server.
order
However, the ordering system permits over-configuration in the order itself. You can up
activation
to 20 CBU features regardless of the current configuration. However, at , only the
activated
capacity that is already installed can be . Note that at activation, you can decide to
activate only a subset of the CBU features that are ordered for the system.
Subcapacity makes a difference in the way that the CBU features are done. On the
full-capacity models, the CBU features indicate the amount of extra capacity needed. If the
amount of necessary CBU capacity is equal to four CPs, the CBU configuration is four CBU
CPs.
The number of CBU CPs must be equal to or greater than the number of CPs in the base
configuration, and all of the CPs in the CBU configuration must have the same capacity
setting. For example, if the base configuration is a two-way D02, providing a CBU
configuration of a four-way of the same capacity setting requires two CBU feature codes.
If the required CBU capacity changes the capacity setting of the CPs, going from model
capacity identifier D02 to a CBU configuration of a four-way E04 requires four CBU feature
codes with a capacity setting of Exx.
If the capacity setting of the CPs is changed, more CBU features are required, not more
physical PUs. Therefore, your CBU contract requires more CBU features if the capacity
setting of the CPs is changed.
CBU can add CPs through LICCC only, and the z13s server must have the correct number of
higher
CPC drawers installed to support the required upgrade. CBU can change the MCI to a
z13s
value than the base setting, but it does not change the model. The CBU feature cannot
decrease
the capacity setting.
A CBU contract must be in place before the special code that enables this capability can be
installed on the z13s server. CBU features can be added to an existing z13s server
non-disruptively. For each machine enabled for CBU, the authorization to use CBU is
available for a definite number of years (one - five).
The installation of the CBU code provides an alternative configuration that can be activated
during an actual emergency. Five CBU tests, lasting up to 10 days each, and one CBU
activation, lasting up to 90 days for a real disaster and recovery, are typically available in a
CBU contract.
temporarily
The alternative configuration is activated , and provides extra capacity greater
permanent
than the server's original, configuration. At activation time, you determine the
capacity that is required for a situation, and you can decide to activate only a subset of the
capacity that is specified in the CBU contract.
The base server configuration must have sufficient memory and channels to accommodate
the potential requirements of the large CBU target configuration. Ensure that all required
functions and resources are available on the backup z13s server, including CF LEVELs for
CF partitions, memory, cryptographic functions, and connectivity capabilities.
When the emergency is over (or the CBU test is complete), the z13s server must be taken
back to its original configuration. The CBU features can be deactivated by the customer at
any time before the expiration date.
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IBM z13s Technical Guide