IBM 990 - Manual (Page 206)

194 IBM
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zSeries 990 Technical Guide
Figure 8-2 CUoD for memory example
This one-book z990 model has two 16 GB memory cards, resulting in 32 GB of installed
memory in total. Therefore, a concurrent memory upgrade within this model A08 can be done
up to the 32 GB limit, via LIC-CC, but a memory upgrade to 40 GB would require the book’s
memory cards replacement by two 32 GB memory cards and is
disruptive .
However, as shown in the example, the upgrade of this model A08 with 24 GB of memory to a
model B16 with 40 GB is
concurrent , as the additional book comes with two memory cards (in
this case, two 8 GB memory cards). The additional 16 GB memory capacity is enabled by
LIC-CC on the second book (Book 1).
In the last part of this example, this model B16 server is concurrently upgraded to 48 GB, by
LIC-CC enabling all the installed memory.
For a logical partition’s memory upgrade, reserved storage must have been previously
defined to that logical partition. It makes use of the LPAR Dynamic Storage Reconfiguration
(DSR) function. DSR allows a z/OS or OS/390 operating system running in a partition to add
its reserved storage to its configuration, if any unused storage exists. When the operating
system running in a partition requests an assignment of a storage increment to its
configuration, PR/SM checks for any free storage and brings it online dynamically.
Concurrent memory upgrades also require that:
Memory must not be running in degraded mode.
Upgrades are disruptive until failing memory cards have been replaced.
2 Memory Cards
(16 GB each)
32 GB
Max
24 GB
2084-A08 24 GB
2 Memory Cards
(16 GB each)
32 GB
Max
24 GB
2084-B16 40 GB
2 Memory Cards
(8 GB each)
Book 0
Book 0
Book 1
2 Memory Cards
(16 GB each)
2084-B16 48 GB
2 Memory Cards
(8 GB each)
16 GB (Max)
Book 0
Book 1
CUoD
+ 16 GB
+ Model upgrade
CUoD
+ 8 GB
16 GB (Max)
32 GB (Max)