Central Storage Layout Following Reconfiguration - IBM Z9 Planning Manual

At a later point in time, the reserved storage from LP-A can be reconfigured to
LP-B. Note that both LPs should specify an RSU value of at least 32 (2048/64) for
reconfigurations of storage to work. From the z/OS software console for LP-A, enter
CF STOR(E=1),OFFLINE. Next, from the z/OS software console for LP-B, enter CF
STOR(E=1),ONLINE. Figure 3-4 shows the resulting storage layout following these
actions. The reserved storage is fully reconfigured without an outage to either LP.
Also, the procedure can be reversed without an outage as well.
1024 GB
1022 GB
1020 GB
1006 GB
Addressable
Storage
1004 GB
990 GB
0 GB
Figure 3-4. Central Storage Layout Following Reconfiguration
Figure 3-5 on page 3-18 and Figure 3-6 on page 3-19 are examples of dynamic
reconfiguration of central storage. For this example, assume the amount of installed
storage is 32 GB. The amount of physical central storage used by hardware system
area (HSA) is 2 GB in this example leaving 30 GB of physical storage for allocation
to LPs. The storage granularity is 64 MB so the HSA addressable storage size is
2048 MB. This leaves 1022 GB of central storage addressability to be allocated to
LPs.
LP-A is defined with an initial amount of 14 GB of central storage, a reserved
amount of 2 GB, and a system determined central storage origin. LP-B is defined
with an initial amount of 14 GB of central storage, with a system determined central
storage origin and an initial amount of 2 GB of expanded storage. The central
storage addressability used to back online expanded storage is always system
determined and in this case is coincidentally but not necessarily contiguous with the
addressability used to back the logical partition's central storage. LP-A and LP-B
are activated and IPLed. Figure 3-5 on page 3-18 shows the resulting storage
layout following these actions.
HSA
RSVD = 2 GB (offline)
ORIG = system determined INIT = 14 GB
RSVD = 2 GB (online)
ORIG = system determined INIT = 14 GB
Unused Addressability
Chapter 3. Determining the Characteristics of Logical Partitions
LP-A
LP-B
3-17