Chapter 8. Capacity upgrades 217
Now let us see the logical upgrade. LP3 has one reserved ICF defined, and since the server
now has one more physical ICF, the reserved ICF can be configured online by the CF image
operator function. This CF image is nondisruptively upgraded to two ICFs.
8.6.2 Planning for nondisruptive upgrades
CUoD, CIU, On/Off CoD, and CBU can be used to concurrently upgrade a z990 server. But
there are some situations that require a disruptive task to use the new capacity just added to
the server. Some of these can be avoided if planning is done in advance. Planning ahead is a
key factor for nondisruptive upgrades. Refer to Table 6-3 on page 148 for more discussion
about nondisruptive planning.
Reasons for disruptive upgrades
These are the current main reasons for disruptive upgrades:
򐂰 Changing the number of logical partitions defined to a z990 server.
The only way to add or delete a logical partition is by a POR using a new IOCDS including
or excluding the new partition.
򐂰 Changing the number of LCSS on a server.
򐂰 Changing the number of subchannels supported on a LCSS.
򐂰 Logical partition processor upgrades when reserved processors were not previously
defined are disruptive to image upgrades.
򐂰 Memory capacity upgrades are disruptive when memory cards replacement is required.
򐂰 Logical partition memory upgrades when reserved storage was not previously defined are
disruptive to image upgrades.
򐂰 Installation of I/O cages is disruptive.
򐂰 An I/O upgrade when the operating system cannot use the Dynamic I/O configuration
function.
Linux and CFCC do not support Dynamic I/O configuration.
If there is no space available in the reserved HSA for the required I/O expansion.
򐂰 An STI rebalancing, when the STI Rebalance feature (Feature Code 2400) is ordered at
the server’s upgrade configuration time.
򐂰 Adding a PCIXCC or a PCICA coprocessor to a logical partition, if not predefined with the
appropriate PCI cryptographic processor number selected in the PCI Cryptographic
Candidate List of the logical partitions image profile.
Recommendations to avoid disruptive upgrades
Based on the previous list of reasons for disruptive upgrades, here are some
recommendations to avoid or at least minimize these situations, increasing the possibilities
for nondisruptive upgrades:
򐂰 Define spare or reserved logical partitions.
A z990 server can have up to 30 logical partitions defined. It is possible to define more
partitions than you need in the initial configuration, just by:
Including more partition names in the IOCP statement RESOURCE. The
spare
partitions
do not need to be activated, so any valid partition configuration can be used
during their definitions. The initial definitions (LPAR mode, processors, and so on) can
be changed later to match the image type requirements.

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