6947ch02.fm Draft Document for Review April 7, 2004 6:15 pm
58 IBM eServer zSeries 990 Technical Guide
PR/SM enables z990 servers to be initialized for logically partitioned operation, supporting up
to 30 logical partitions. Each logical partition can run its own operating system image in any
image mode, independently from the other logical partitions.
A logical partition can be activated or deactivated at any time, but changing the number of
defined logical partitions is disruptive, as it requires a Power-on Reset (POR). Some facilities
may not be available to all operating systems, as they may have software corequisites.
Each logical partition has the same resources as a “real” CPC, which are:
򐂰Processor(s)
Called Logical Processor(s), they can be defined as CPs, IFLs, ICFs, or zAAPs. They can
be dedicated to a partition or shared between partitions. When shared, a processor weight
can be defined to provide the required level of processor resources to a logical partition.
Also, the capping option can be turned on, which prevents a logical partition from
acquiring more than its defined weight, limiting its processor consumption.
For z/OS Workload License Charge (WLC), a logical partition “Defined Capacity” can be
set, enabling the soft capping function.
ESA/390 mode logical partitions can have CPs and zAAPs logical processors. Both logical
processor types can be defined as either all dedicated or all shared. The zAAP support is
planned to be introduced by z/OS 1.6.
Only Coupling Facility (CF) partitions can have both dedicated and shared logical
processors defined.
Figure 2-16 shows the logical processor assignment screen of the Customize Image
Profile on the Hardware Management Console (HCM), for an ESA/390 mode image. This
panel allows the definition of:
– Dedicated or shared logical processors, including CPs and zAAPs (remember that
zAAPs initially appear as “Integrated Facility for Applications” on HCM panels).
– The initial weight, optional capping and Workload Manager options for shared CPs
(shared zAAPs weight equals to CPs weight, but share calculation is based on the sum
of ICFs, IFLs and zAAPs weights).
– The number of initial and optional reserved processors (CPs).
– The optional number of initial and reserved integrated facility for application (zAAPs).