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## zIIP installation 

One CP must be installed with or before any zIIP is installed. In z14 ZR1, the zIIP-to-CP ratio is 2:1, which means that up to 12 zIIPs can be characterized. The allowable number of zIIPs for each feature is listed in Table 3-3. 

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zIIPs are orderable by using FC 1067. Up to two zIIPs can be ordered for each CP or marked CP configured in the system. 

PUs that are characterized as zIIPs within a configuration are grouped into the zIIP pool. This configuration allows zIIPs to have their own processing weights, independent of the weight of parent CPs. The zIIP pool can be seen on the hardware console. 

The number of permanent zIIPs plus temporary zIIPs cannot exceed twice the number of purchased CPs plus temporary CPs. Also, the number of temporary zIIPs cannot exceed the number of permanent zIIPs. 

## zIIPs and logical partition definitions 

zIIPs are dedicated or shared, depending on whether they are part of an LPAR with dedicated or shared CPs. In an LPAR, at least one CP must be defined before zIIPs for that partition can be defined. The number of zIIPs that are available in the system is the number of zIIPs that can be defined to an LPAR. 

LPAR:  In an LPAR, as many zIIPs as are available can be defined together with at least one CP. 

## 3.5.6 System assist processors 

A system assist processor (SAP) is a PU that runs the channel subsystem LIC to control I/O operations. All SAPs run I/O operations for all LPARs. All models feature standard SAPs configured. The number of standard SAPs on the z14 ZR1 is two, regardless of the CPC drawer feature. 

## SAP configuration 

A standard SAP configuration provides a well-balanced system for most environments. However, some application environments have high I/O rates, typically Transaction Processing Facility (TPF) environments. In this case, more SAPs can be ordered. Assigning of more SAPs can increase the capability of the channel subsystem to run I/O operations. 

## Optional other orderable (extra) SAPs 

The option to order more SAPs is available on all z14 ZR1 features (FC 1066). These extra SAPs increase the capacity of the channel subsystem to run I/O operation, which is suggested for TPF environments. In z14 ZR1 systems, the maximum number of optional (extra) orderable SAPs is two, regardless of the CPC drawer feature. 

