CA Dynam for VSE User Guide

Managing the VTOC
Deleting Expired Files
When you are processing an allocation request for a volume without a VTOC
index, expired files that were allocated by CA Dynam/D are automatically
deleted.
But automatic deletion is not performed on volumes having VTOC indexes,
because all allocation information is maintained within the VTOC index.
Instead, the indexes are automatically rebuilt each day on or after 8:00 a.m.
Any expired data sets that were allocated by CA Dynam/D are deleted at this
time.
Benchmark tests have shown that the use of indexed VTOCs can significantly
improve performance and overall system throughput, even when used on
DASD volumes not under the control of CA Dynam/D.
Indexed VTOC Processing
CA Dynam-indexed VTOC processing can be used effectively on all CKD
volumes except perhaps volumes which contain only VSAM data spaces. On
FBA devices, VTOC indexes should be used only if there are more than 200
files on the volume. Increase the VTOC CISIZE to 4K or 8K to improve
performance on FBA volumes with fewer than 200 files.
To use VTOC indexes, all systems must be running VSE r2 and above. If
volumes having VTOC indexes are to be updated by more than one CPU, all
updating systems must be running CA Dynam VTOC management. For more
information about how to define and initialize VTOC indexes, see the DYNCAT
VTOC command in the chapter "Maintaining the Catalog DYNCAT Program."
CA Dynam/D VTOC management is similar in concept to the OS Data Facility
Device Support VTOC management. For more information, see the IBM
publication, Data Facility Device Support: General Information.
Chapter 4: Disk File Management 4–13