VSAM Tuning and Performance

VSAM Tuning and Performance


This course is designed for those z/OS technicians who require a greater understanding of VSAM within their z/OS installation. The aim is to allow them to analyse their use of VSAM with the aim of improving performance and reliability whilst reducing errors.


Delegates should have at least a basic knowledge of TSO/ISPF and JCL, as taught in our z/OS TSO/ISPF Workshop and z/OS Job Control Language courses.

An appreciation of VSAM, IDCAMS and general buffering would be helpful.


2 days. Hands on.

Course Objectives

After successfully completing this course, delegates will:

  • Understand the main concepts of the VSAM file.
  • Understand Access Methods Services program and its parameters.
  • Have a greater understanding of COBOL, COBOL II, PL1 and Assembler programming in relation to VSAM files.
  • Tune VSAM files.

Course Content

Introduction to VSAM
Evolution of Access Methods:
• DAM.
VSAM File Types:
• LDS.
Basic VSAM Terminology:
• Cluster.
• Component.
• Data.
• Index.
• Freespace.
• Control Interval.
• Control Area.
• Splits.

Disks and Catalogs
• Blocks.
• Tracks.
• Cylinders.
• VSAM Catalog.
• ICF Catalog.
• Mastercats.
• Usercats.
• Alias.
The order of a Catalog Search.
Data Facility Product (DFP) Concepts.
IDCAMS Commands:

Rules of IDCAMS
IDCAMS Syntax Rules.
JCL Requirements:
• MVS.
• VSE.
• ESA.
Condition Codes.
MODAL options.

Creating a VSAM Cluster
• LDS.
Example of an "IDEAL" Define.

Creating a LISTCAT
Interpreting a LISTCAT:
• Field by Field.
• At a Glance.

Tuning a VSAM Cluster
VSAM Tuning Concepts.
Using your LISTCAT.
• Space Allocations.
• Indexes.
Formulas and Calculations.
Disk Tables.

Reorganizing a VSAM Cluster
Backing Up a Cluster.
Deleting a Cluster.
Reusing a Cluster.
Loading Data.
IDCAMS Commands:

Alternate Indexes
Alternate Index Concepts.
Building a path.
Building an alternate AIX.
Tuning an AIX.
JCL Requirements.

Optimizing VSAM Use
Batch versus CICS use.
• Cross Region.
• Cross System.
• NSR.
• LSR.
• FCT.
• Shutdown Statistics.

COBOL Programming
Batch COBOL Rules:
• Select/Assign Clause.
• FD Clause.
• File Verbs (Open, Write, etc...).
VSAM Differences for COBOL II.
• AIX.

PLI Programming
Batch PLI Rules:
• Declare (DCL).
• File Verbs (Open, Write, etc...).
• AIX.

Assembler Programming
VSAM Macros:
• ACB.
• RPL.
• OPEN, etc...

CICS Programming
CICS VSAM Concepts:
• FCT Definition.
• EXEC CICS Commands.
• AIX.

Other VSAM Concepts
Manipulating a File:
• Print Contents of a File.
• Alter Definition of a File.
Maintaining File Integrity:
• Verify End-of-File Marker.
• Compare Catalog Entry to Physical File Definition.
Other Defines:
• Defining a NONVSAM File.
• Defining a Generation Data Group.
Cache Memory Concepts.

Linear Data Sets (LDS)
Linear File Concepts:
• Virtual Storage Windowing.
• Data/Hyper Spaces.
Define Cluster Example.
Programming Example (COBOL II).

Data Facility Storage Management Subsystems (DFSMS)
System Managed Storage:
• Data Classes.
• Storage Classes.
• Management Classes.
• Storage Groups.
Changes to VSAM.
JCL Changes.

Virtual Courses

ALL of our courses can be delivered virtually. And our Bath public schedule of courses are now available as live virtual sessions, using the popular Zoom Virtual Classroom and remote labs. Delegates can test their access at: www.zoom.us/test

Public Courses

There are no upcoming events

On-Site Courses

Can't attend one of our public classes? Booking for multiple people?

All our courses are available on your site! Delivered for your staff, at your premises.

Contact us to find out more...