Characteristics

LPs can have the following characteristics. For more information or details about exceptions to any of these characteristics, see Determining the characteristics.

• The maximum number of LPs you can define on a z17 is 85 for models ME1 and ML1. For models ME2 and MER (machine type 9176), the maximum number of LPs is 40.
• LPs can operate in General , Linux-Only, z/VM®, Coupling facility, SSC mode.
• The storage for each LP is isolated. Central storage cannot be shared by LPs.
• Using dynamic storage reconfiguration, an LP can release storage or attach storage to its configuration that is released by another LP.
• All channel paths can be defined as reconfigurable. Channel paths are assigned to LPs. You can move reconfigurable channel paths between LPs using tasks available from either the Hardware Management Console or the Support Element console. If the control program running in the LP supports physical channel path reconfiguration, channel paths can be moved among LPs by control program commands without disruption to the activity of the control program.
• MIF allows channel paths to be shared by two or more LPs at the same time. All CHPID types except CVC and CBY can be shared.
• The total number of logical processors that can be defined is 208 for models ME1 and ML1. For models ME2 and MER (machine type 9176), the total number of logical processors that can be defined is 82.
• CPs can be dedicated to LPs or shared by them. CPs that you define as dedicated to an LP are not available to perform work for other active LPs. The resources of shared CPs are allocated to active LPs as needed. You can cap (limit) shared CP resources, if required.

  Figure 1 shows some of the characteristics that can be defined for an LP. You can view each LP as a CPC operating within the physical CPC.

• You cannot define a mix of shared and dedicated CPs for a single LP. CPs for an LP are either all dedicated or all shared. However, you can define a mix of LPs with shared CPs and LPs with dedicated CPs and activate them concurrently.
• For security purposes, you can:
  • Reserve reconfigurable channel paths for the exclusive use of an LP (unless overridden by the operator)
  • Limit the authority of an LP to read or write any IOCDS in the configuration and limit the authority of an LP to change the I/O configuration dynamically
  • Limit the authority of an LP to retrieve global performance data for all LPs in the configuration
  • Limit the authority of an LP to issue certain control program instructions that affect other LPs
• A coupling facility LP has a maximum of 16 processors (ICFs or CPs), regardless of the model.