IBM z13s Technical Manual page 147

The weight and number of online logical processors of an LPAR can be dynamically
managed by the LPAR CPU Management function of the Intelligent Resource Director
(IRD). These processors can then be used to achieve the defined goals of this specific
partition and of the overall system. The provisioning architecture of the servers, described
in Chapter 8, "System upgrades" on page 311, adds another dimension to the dynamic
management of LPARs.
PR/SM is enhanced to support an option to limit the amount of physical processor
capacity that is consumed by an individual LPAR when a PU is defined as a
general-purpose processor (CP) or an IFL shared across a set of LPARs.
This enhancement is designed to provide a physical capacity limit that is enforced as an
absolute (versus relative) limit. It is not affected by changes to the logical or physical
configuration of the system. This physical capacity limit can be specified in units of CPs or
IFLs. The "Change LPAR Controls" and "Customize Activation Profiles" tasks on the
Hardware Management Console have been enhanced to support this new function.
For the z/OS Workload License Charges (WLC) pricing metric, and metrics that are based
on it, such as Advanced Workload License Charges (AWLC), an LPAR
can be set. This defined capacity enables the soft capping function. Workload charging
introduces the capability to pay software license fees based on the processor utilization of
the LPAR on which the product is running, rather than on the total capacity of the system:
– In support of WLC, the user can specify a defined capacity in MSU per hour. The
defined capacity sets the capacity of an individual LPAR when soft capping is selected.
The defined capacity value is specified on the Options tab in the Customize Image
Profiles window.
– WLM keeps a 4-hour rolling average of the processor usage of the LPAR. When the
4-hour average processor consumption exceeds the defined capacity limit, WLM
dynamically activates LPAR capping (soft capping). When the rolling 4-hour average
returns below the defined capacity, the soft cap is removed.
For more information about WLM, see System Programmer's Guide to: Workload
Manager, SG24-6472. For a review of software licensing, see 7.16.1, "Software licensing
considerations" on page 305.
Weight settings: When defined capacity is used to define an uncapped LPAR's
capacity, carefully consider the weight settings of that LPAR. If the weight is much
smaller than the defined capacity, PR/SM uses a discontinuous cap pattern to achieve
the defined capacity setting. This configuration means PR/SM alternates between
capping the LPAR at the MSU value corresponding to the relative weight settings, and
no capping at all. It is best to avoid this scenario, and try to establish a defined capacity
that is equal or close to the relative weight.
Memory: Memory, either main storage or expanded storage, must be dedicated to an
LPAR. The defined storage must be available during the LPAR activation. Otherwise, the
LPAR activation fails.
Reserved
storage can be defined to an LPAR, enabling nondisruptive memory addition to
and removal from an LPAR, by using the LPAR dynamic storage reconfiguration (z/OS and
z/VM). For more information, see 3.7.5, "LPAR dynamic storage reconfiguration" on
page 129.
Chapter 3. Central processor complex system design
defined capacity
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