Hardware System Area (Hsa); Logical Partitioning - IBM z13s Technical Manual

Removal of support for Expanded Storage (XSTORE): z/VM V6.3 is the last z/VM
release that supports Expanded Storage (XSTORE) for either host or guest use. The IBM
z13 and z13s servers are the last z Systems servers to support Expanded Storage
(XSTORE).
All statements regarding IBM plans, directions, and intent are subject to change or
withdrawal without notice. Any reliance on these statements of general direction is at the
relying party's sole risk and will not create liability or obligation for IBM.
z13s servers can run in LPAR or Dynamic Partition Manager (DPM) mode. For DPM mode,
see Appendix E, "IBM Dynamic Partition Manager" on page 501.
When running in LPAR mode, storage is placed into a single storage pool that is called the
LPAR single storage pool
back to main storage as needed when partitions are activated or deactivated.
LPAR single storage pool
In LPAR mode, storage is not split into main storage and expanded storage at POR. Rather,
the storage is placed into a single main storage pool that is dynamically assigned to
expanded storage and back to main storage, as needed.
On the HMC, the storage assignment tab of a reset profile shows the customer storage.
Customer storage
and, optionally, expanded storage.
Activation of LPARs and dynamic storage reconfiguration cause the storage to be assigned to
the type that is needed (central or expanded). It does not require a POR.

3.6.4 Hardware system area (HSA)

The HSA is a non-addressable storage area that contains system LIC and
configuration-dependent control blocks. On z13s servers, the HSA has a fixed size of 40 GB
and is not part of the purchased memory that customers order and is installed by IBM.
The fixed size of the HSA eliminates planning for future expansion of the HSA because the
hardware configuration definition (HCD) input/output configuration program (IOCP) always
reserves space for the following items:
Three channel subsystems (CSSs)
15 LPARs in the first two CSSs and 10 LPARs for the third CSS for a total of 40 LPARs
Subchannel set 0 with 63.75-K devices in each CSS
Subchannel set 1 with 64-K devices in each CSS
Subchannel set 2 with 64-K devices in each CSS
The HSA has sufficient reserved space to allow for dynamic I/O reconfiguration changes to
the maximum capability of the processor.

3.7 Logical partitioning

This section addresses logical partitioning features.
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IBM z13s Technical Guide
. This pool can be dynamically converted to expanded storage and
is the total installed storage. LPARs are still defined to have main storage