IBM 990 - Manual (Page 224)

212 IBM
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zSeries 990 Technical Guide
Figure 8-11 Shared logical partitions upgrade example
There are two activated logical partitions: LP1, having seven shared (SHR) logical CPs and
two reserved CPs defined, and LP2, having only two shared (SHR) logical CPs defined. Note
that the number of reserved CPs for a logical partition can be higher than the number of
installed PUs. This allows nondisruptive image upgrades even when new books are installed.
This example shows an upgrade to the 2084-B16 software model 309, achieved by adding
concurrently, one more book and LIC-CC, enabling two more CPs to the physical
configuration. Seven spare PUs are available for future processor upgrades. The physical
upgrade ends here.
At this point, before any other configuration changes are made, the images with shared
logical CPs running on this server can experience performance improvements. As there is
now more available capacity (physical processors) to be used by all logical shared CPs, the
“logical-to-physical processors ratio” is reduced. In this example, before the upgrade, there
were nine shared logical CPs to be dispatched into seven physical CPs. If all nine logical CPs
have tasks to run, two of them have to wait. After the physical upgrade, up to nine logical CPs
can run at the same time.
Now let us see the logical upgrades. Since there is no activated partition with dedicated CP,
any partition can have up to nine activated logical CPs.
Partition LP1 has two reserved CPs defined and, if the operating system running on it has the
capability of configuring processors online, this partition can be nondisruptively upgraded to
nine CPs, as shown in this example.
Partition LP2 has no reserved CPs, so it cannot be nondisruptively upgraded. If any upgrade
for this partition is required, it will require deactivation to configure more CPs.
CP0 CP1 CP2 CP3 Spare CP4 CP5 CP6
Book 0
Logical
CP0
SHR
Logical
CP0
SHR
Logical
CP1
SHR
Logical
CP1
SHR
Logical
CP2
SHR
Logical
CP3
SHR
Logical
CP4
SHR
Logical
CP5
SHR
Logical
CP6
SHR
Res
CP
Res
CP
CP0 CP1 CP2 CP3 Spare Spare Spare Spare CP4 CP5 CP6 Spare Spare Spare
Book 0 Book 1
Logical
CP0
SHR
Logical
CP0
SHR
Logical
CP1
SHR
Logical
CP1
SHR
Logical
CP2
SHR
Logical
CP3
SHR
Logical
CP4
SHR
Logical
CP5
SHR
Logical
CP6
SHR
Logical
CP7
SHR
Logical
CP8
SHR
CP7 CP8
LP1
LP2
2084-A08
Model 307
LP1
LP2
2084-B16
Model 309