IBM z13s, Technical Manual

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Chapter 7. Software support
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7.3.4 Maximum main storage size
Table 7-6 lists the maximum amount of main storage that is supported by current operating
systems. A maximum of 4 TB of main storage can be defined for an LPAR on a z13s. If an I/O
drawer is present (as carry-forward), the LPAR maximum memory is limited to 1 TB.
Expanded storage, although part of the z/Architecture, is used only by z/VM.
Table 7-6 Maximum memory that is supported by the operating system
7.3.5 Flash Express
IBM z13s continues support for
Flash Express
, which can help improve the resilience and
performance of the z/OS system. Flash Express is designed to assist with the handling of
workload spikes or increased workload demand that might occur at the opening of the
business day, or in a workload shift from one system to another.
z/OS is the first OS to use Flash Express storage as storage-class memory (SCM) for paging
store and supervisor call (SAN Volume Controller)
memory dumps. Flash memory is a faster
paging device compared to a hard disk drive (HDD). SAN Volume Controller memory dump
data capture time is expected to be substantially reduced. As a paging store, Flash Express
storage is suitable for workloads that can tolerate paging. It does not benefit workloads that
cannot afford to page. The z/OS design for Flash Express storage does not completely
remove the virtual storage constraints that are created by a paging spike in the system.
However, some scalability relief is expected because of faster paging I/O with Flash Express
storage.
Flash Express storage is allocated to an LPAR similarly to main memory. The initial and
maximum amount of Flash Express Storage that is available to a particular LPAR is specified
at the Support Element (SE) or Hardware Management Console (HMC) by using a new Flash
Storage Allocation window.
The Flash Express storage granularity is 16 GB. The amount of Flash Express storage in the
partition can be changed dynamically between the initial and the maximum amount at the SE
or HMC. For z/OS, this change also can be made by using an operator command. Each
Operating system Maximum supported main storage
a
a. z13s supports 4 TB user configurable memory per server.
z/OS z/OS V2R1 and later support 4 TB
a
.
z/VM z/VM V6R3 supports 1 TB.
z/VM V6R2 supports 256 GB
z/VSE z/VSE V5R1 and later support 32 GB.
z/TPF z/TPF supports 4 TB.
a
CFCC Level 21 supports up to 3 TB per server.
a
zACI Supports up to 3 TB per server.
a
Linux on z Systems
(64-bit) SUSE Linux Enterprise Server 12 supports 4 TB.
a
SUSE Linux Enterprise Server 11 supports 4 TB.
a
SUSE Linux Enterprise Server 10 supports 4 TB.
a
Red Hat RHEL 7 supports 3 TB.
a
Red Hat RHEL 6 supports 3 TB.
a
Red Hat RHEL 5 supports 3 TB.
a