IBM eServer zSeries 990 Technical Guide

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 partition’s 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.