IBM z/OS - Manual (Page 61)

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availability. This form of clustering, known as single system
image, also provides tremendous scale. Up to 32 zSeries
servers with z/OS can appear as a single image for
data sharing applications (see previous section, Parallel
Sysplex Clustering Technology).
CICS/VSAM enabled for 24x7 availability
DFSMS Transactional VSAM Services (DFSMStvs) allows
you to share VSAM data sets across CICS, batch, and
object-oriented applications on z/OS or distributed sys-
tems. DFSMStvs can enable concurrent shared updates
of recoverable VSAM data sets by CICS transactions, mul-
tiple batch applications, and 24-hour availability of CICS
and batch applications. DFSMStvs is built on top of VSAM
record-level sharing (RLS), which permits sharing of recov-
erable VSAM data sets at the record level.
System-Managed CF Structure Duplexing
System-Managed Coupling Facility (CF) Structure Duplex-
ing is designed to signifi cantly enhance Parallel Sysplex
availability. It can provide a robust failure recovery capa-
bility via CF structure redundancy, and it can enhance
Parallel Sysplex ease of use by helping to reduce the
complexity of CF structure recovery. These benefi ts can
be achieved by creating a duplicate (or duplexed) copy
of a CF structure and then maintaining the two struc-
ture instances in a synchronized state during normal CF
operation. In the event of a CF related failure (or even a
planned outage of a CF), failover to the remaining copy of
the duplexed structures can be initiated and quickly com-
pleted transparent to the CF structure user and without
manual intervention.
JES2 and JES3
JES2 and JES3 handle the submission of work and the
distribution of output for the Base Control Program. JES2
exercises independent control over its job processing
functions, whereas JES3 exercises centralized control.
• In z/OS 1.2, JES2 and JES3 allow an installation to have
up to 999,999 jobs managed at any single point in time.
In addition, both provide the installation the ability to
obtain (spinoff) their JESlog data sets prior to job com-
pletion.
• The JES2 Health monitor, in z/OS 1.4, provides improved
diagnostics. Even when JES2 is not responding to com-
mands, the JES2 monitor, running in a separate address
space, will be able to provide information about JES2’s
status. JES2 also provides enhanced recovery from cor-
rupted checkpoint data to prevent multisystem outages
• In z/OS 1.4, JES3 provides additional tolerance for ini-
tialization errors and the MAINPROC refresh function
which enables the dynamic addition of systems to the
sysplex.
System Management Services
z/OS Version 1 Release 6 base elements
HCD
SMP/E
Managed System Infrastructure for Setup
Managed System Infrastructure for Operations
z/OS Version 1 Release 6 optional priced features
RMF
SDSF
HCM