IBM 990 - Manual (Page 201)

Chapter 8. Capacity upgrades 189
These LIC-CC based PU conversions, as listed in Table 2-7 on page 65, require that at least
one PU (CP, ICF or IFL) remain untouched; otherwise, the conversion is disruptive. The PU
conversion generates a new LIC-CC that can be installed concurrently in two steps. First, the
assigned PU is removed from the z990 configuration. Second, the newly available PU is
activated as the new PU type.
Logical partitions may also need to “free” PUs to be converted, and the operating systems
must have the “configure offline/online” capability to do the PU conversion nondisruptively.
Model upgrades
The z990 servers have both a server model (2084-xxx) and a software model (3xx).
The server model indicates how many books are present on the configuration, while the
software model indicates how many CPs are present for software billing-related purposes.
z990 model upgrades always require physical hardware (books) addition. z990 servers
upgrades can change either, or both, the server and the software models:
On LIC-only upgrades:
– May change the server’s software model (3xx) if additional CPs are included.
– Cannot change the server’s model (2084-xxx), as no additional books can be included.
On hardware installation upgrades:
– May change the server’s model (2084-xxx) if additional books are included.
– May change the server’s software model (3xx) if additional CPs are included.
Both the server and the software models can be concurrently upgraded.
Concurrent upgrades can be accomplished in both planned and unplanned upgrade
situations.
Planned upgrades
Planned upgrades can be done by the Capacity Upgrade on Demand (CUoD), the Customer
Initiated Upgrade (CIU), or the On/Off Capacity on Demand (On/Off CoD) functions.
CUoD and CIU are functions available on z990 servers that enable concurrent and permanent
capacity growth of a z990 server.
CUoD can concurrently add processors (CPs, IFLs, ICFs, and zAAPs), memory, and I/O ports
to an existing server. CUoD requires IBM service personnel for the upgrade.
CIU can concurrently add processors (CPs, IFLs, ICFs, and zAAPs) and memory up to the
limit of the installed book(s) of an existing server. CIU is initiated by the customer via the Web
using IBM Resource Link, and makes use of CUoD techniques. CIU requires a special
contract.
On/Off CoD is a function available on z990 servers that enables concurrent and temporary
capacity growth of a z990 server. On/Off CoD can be used for customer peak workload
requirements, for any length of time.
Important: If the z990 STI Rebalance feature (FC 2400) is selected and effectively results
in STI rebalancing, the server upgrade will be disruptive and this outage must be planned.
The z990 STI Rebalance feature may also change the Physical Channel ID (PCHID) of
ICB-4 links, requiring a corresponding update on the server I/O definition via HCD or HCM.