content_image/977653.jpg
Unused CPs are not a factor when establishing the millions of service units (MSU) value that is used for charging monthly license charge (MLC) software, or when charged on a per-processor basis. 

## 2.8.1 Upgrades 

Concurrent upgrades of CPs, IFLs, ICFs, zIIPs, or SAPs are available for the z15 server. However, concurrent PU upgrades require that more PUs are installed but not activated. 

Spare PUs are used to replace defective PUs. Two spare PUs always are on a z15 server. In the rare event of a PU failure, a spare PU is activated concurrently and transparently and is assigned the characteristics of the failing PU. 

If an upgrade request cannot be accomplished within the configuration, a hardware upgrade is required. 

The following upgrade paths for the z15 are shown in Figure 2-29: 

<img src='content_image/977653.jpg'>

GLYPH<SM590000> z15 to z15 upgrades: 

– T01 Max34 to Max71, Max108 are concurrent 

– No upgrade to Max154 or Max190 (these features are Factory built only) 

– More I/O drawers can be added based on available space in current frames or I/O expansion frames 

GLYPH<SM590000> Any z13 to z15: 

– Feature conversion of installed zAAPs to zIIPs (default) or another processor type 

– For installed OnDemand Reco rds, change temporary zAAPs to zIIPs. Stage the record 

GLYPH<SM590000> Any z14 M0x to z15 

Note:  The z15 CPC cannot be member in an Ensemble managed by Unified Resource Manager. 

