FDRREORG offers a fast, flexible and intelligent solution for reorganizing VSAM KSDS,
Alternate Index (AIX) files, and for compressing PDS data sets. Users of the Innovation
Access Method (IAM)
can also use FDRREORG to reorganize their IAM files.
FDRREORG also eliminates much of the manual “hit-and-miss” approach inherent
in IDCAMS and IEBCOPY.
User-specified selection criteria ensure that only the files that need reorganization
or compression are selected, further reducing the utilization of valuable CPU resources,
yet still ensuring that the files that really need attention do not get overlooked.
Re-Organizing VSAM and Compressing PDSs on an “as needed” basis can greatly
reduce the time it takes to complete the overall tasks, and, therefore, reduces the level
of interruption to the applications that use those files.
Many applications running under z/OS still use VSAM as the underlining file structure.
Some VSAM files can be very heavily used and can become extremely large. As usage
and/or size of a VSAM file increases, the performance of the application(s) using
that file can be significantly impaired.
An IDCAMS re-organization of the VSAM file can improve the performance, but the ageing
utility is notoriously slow and lacks the automation features required by today’s large z/OS shops.
- FDRREORG provides a faster, more efficient and more flexible
alternative to IDCAMS for logically reorganizing VSAM KSDS, Alternate Index (AIX)
and IAM data sets.
- FDRREORG can provide a 20% to 60% reduction in wall clock,
CPU time and EXCPs compared to IDCAMS.
- FDRREORG saves time and resources (e.g. CPU) by only re-organizing the
VSAM files that really need it, bypassing those that don’t.
- FDRREORG reduces application downtime by speeding up the VSAM
re-organizations that it does need to do.
- FDRREORG’s parallel backup option ensures optimum performance
during the backup phase of a re-organization.
When traditional methods of VSAM reorganization are used (e.g. IDCAMS), the process
is usually scheduled as a regular job, and the selection of files to be processed
is based upon some previous experience.
Using this approach, reorganizations are often carried out on files were there is only
a marginal benefit. And in other cases, files that need a reorganization get overlooked.
FDRREORG’s intelligent selection criteria helps to eliminate these problems.
A single job can be scheduled to run at regular intervals, looking at all files that may
need to be reorganized, but only reorganize the ones that really need it.
See the Technical Detail page for an example of FDRREORG job to
re-organize VSAM files.
PDS data sets also require special attention, but the standard utility
IEBCOPY lacks the intelligence and performance to deal with PDSs in large numbers:
- FDRREORG provides the same intelligent selection process for
PDSs as it does for VSAM (described above).
- FDRREORG can also expand and empty PDS data sets.
- FDRREORG can provide a 50% to 90% reduction in elapsed time
compared to IEBCOPY, as well as reducing CPU and I/Os too.
Like an IEBCOPY compress-in-place, FDRREORG compresses PDS data sets by
placing all active members to the beginning of the PDS to allow room for
new members to be added.
FDRREORG can be transparently invoked, without modification to the
operating system, so that when IEBCOPY is called to compress PDS data
sets, FDRREORG takes over and completes the task.
See the Technical Detail page for an example of FDRREORG job to compress PDSs.
A simulation mode is provided with FDRREORG to allow you to test and verify your selection
criteria. before running a VSAM Re-Organization or PDS Compression. The simulation report
shows exactly which files would have been selected if the process were run for real.
After an execution of a “real” FDRREORG, a summary report like the one shown below is
produced to show which files were selected for processing, together with information
about their before/after status:
FDRREORG can move or consolidate multi-volume VSAM files from one
location to another – e.g. a VSAM file spread over several 3390-3s
can be consolidated onto a single 3390-9 with FDRREORG.
However, for more general information on consolidating DASD (e.g. moving
from 3390-3s to 3390-9s) see FDRMOVE.
For more introductory information on FDRREORG, see the Product Portfolio Sheet
For JCL examples of FDRREORG, see the Technical Detail section.
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