IBM z13s, Technical Manual

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IBM z13s Technical Guide
partition’s Flash Express storage is isolated like the main storage, and sees only its own
space in the flash storage space.
Flash Express provides 1.4 TB of storage per feature pair. Up to four pairs can be installed,
for a total of 5.6 TB. All paging data can easily be on Flash Express storage, but not all types
of page data can be on it. For example, virtual I/O (VIO) data always is placed on an external
disk. Local page data sets are still required to support peak paging demands that require
more capacity than provided by the amount of configured SCM.
The z/OS paging subsystem works with a mix of internal Flash Express storage and external
disk. The placement of data on Flash Express storage and external disk is self-tuning, based
on measured performance. At IPL time, z/OS detects whether Flash Express storage is
assigned to the partition. z/OS automatically uses Flash Express storage for paging unless
specified otherwise by using
PAGESCM=NONE in IEASYSxx. No definition is required for
placement of data on Flash Express storage.
The support is delivered in the z/OS V1R13 real storage manager (RSM) Enablement
Offering Web Deliverable (FMID JBB778H) for z/OS V1R13. Dynamic reconfiguration support
for SCM is available as a web deliverable. The installation of this web deliverable requires
careful planning because the size of the Nucleus, extended system queue area (ESQA) per
CPU, and RSM stack is increased. Also, a new memory pool for pageable large pages is
added. For web-deliverable code on z/OS, see the z/OS downloads website:
http://www.ibm.com/systems/z/os/zos/downloads/
The support also is delivered in z/OS V2R1 (included with the base product) or later.
Linux on z Systems also offers the support for Flash Express as an SCM device. This support
is useful for workloads with large write operations with a block size of 256 KB or more. The
SCM increments are accessed through extended asynchronous data mover (EADM)
subchannels.
Table 7-7 lists the minimum support requirements for Flash Express.
Table 7-7 Minimum support requirements for Flash Express
Flash Express usage by CFCC
Coupling facility control code (CFCC) Level 21 supports Flash Express. Initial CF Flash usage
is targeted for WebSphere MQ shared queues application structures. Structures can now be
allocated with a combination of real memory and SCM that is provided by the Flash Express
feature. For more information, see “Flash Express exploitation by CFCC” on page 294.
Flash Express usage by Java
z/OS Java SDK 7 SR3, CICS TS V5.1, WebSphere Liberty Profile 8.5, DB2 V11, and
IMS V12 are targeted for Flash Express usage. There is a statement of direction to support
traditional WebSphere V8. The support is for just-in-time (JIT) Code Cache and Java Heap to
improve performance for pageable large pages.
Operating system Support requirements
z/OS z/OS V1R13
a
a. Web deliverable and PTFs are required.
Linux on z Systems SUSE Linux Enterprise Server 12
SUSE Linux Enterprise Server 11 SP3
RHEL6
RHEL7