Data Storage Essentials for Z Systems

This course provides an overview of data storage concepts for z/OS system environments. It covers the range of disciplines and skills required to give a good understanding of how the software and hardware interacts, providing a powerful data storage management environment. This course is most suitable for organisations using the IBM HSM software.

This course is available 'on demand' (minimum 2 students) for open-enrolment presentations and also for exclusive, one-company presentations.

What you will learn

On successful completion of this course you will be able to:

  • explain the principles and mechanics of I/O processing
  • describe storage management in a z/OS environment
  • list and describe data storage hardware
  • explain the purpose and functions of Hardware Configuration Definition (HCD)
  • use HCD to investigate an I/O configuration
  • describe and explain the concepts of the z/OS access methods
  • describe the structure and design of VSAM files
  • use the Access Method Services utility program IDCAMS to define, load, backup, monitor and manipulate VSAM datasets with particular emphasis on the KSDS file type
  • understand the contents when listing a catalogued dataset
  • understand the contents of ACS routines
  • explain the concepts of SMS
  • describe HSM and its main features.

Who Should Attend

This course is suitable for anyone working in a support role in a z/OS environment who requires a good understanding of data storage.


A general knowledge of MVS concepts the ability to use JCL and Utility programs.


5 days

Fee (per attendee)

£2475 (ex VAT)


This includes free online 24/7 access to course notes.


Hard copy course notes are available on request from

at £50.00 plus carriage per set.

Course Code



I/O Processing

Why I/O processing?; what is I/O?; MVS support for I/O processing software; MVS and I/O processing; Application I/O; the application program; the DD statement; going to the Access Method; the Access Method; getting the channel program started; EXCP - an IOS Driver; IOS 'Front End'; actually starting the I/O; the I/O engine at work; the Channel Sub-System (CSS); Hardware System Area (HSA); "The I/O Farm"; the I/O Interrupt; IOS Post processing; back to the Access Method; the I/O process from A to Z; starting the I/O; going back from starting the I/O; I/O complete; caching concepts; Read Hit; Write commands; Write Hit; Read Miss; Write Miss; cache modes; review questions - Input/Output processing.

Focus on Storage Management

What is storage management?; Space management roles; DFSMS products; DFSMS Optimizer; NaviQuest feature; advantages of an SMS environment; availability management; performance management.

Data Storage Hardware

Direct Access Storage Devices (DASD): I/O operations on disks; RMF reports; DASD controllers; Caching concepts; Read Hit; Write commands; Write Hit; Read Miss; Write Miss; Cache modes; Record level caching; Peer to Peer Remote Copy (PPRC); Concurrent Copy; Extended Format Data Sets; Sequential Data Striping; RAID technology; RAID categories 0, 1, 2 & 3; RAID categories 4, 5 and 6; IBM's Flashcopy; Extended Address Volumes; Tape devices; Virtual Tape Server; Virtual Tape configurations.

Introduction to HCD

I/O configuration principles; I/O configuration practicalities; I/O configuration addressing; HCD definition process; Objects managed by HCD; Load member of parmlib; IODF processing at IPL; HCD primary panel; Creating a new work IODF; Defining the new configuration menu; Defining a Channel; Defining a Control Unit; Defining an I/O Device; Pull-down menu action bar; Goto pull down menu; Filter pull down menu; Backup pull down menu; Query pull down menu; Help pull down menu; Context menus; PF keys; Keyboard navigation.

VSAM Overview

MVS and I/O processing; The access methods; The IOS Drivers; The I/O Supervisor (IOS); The Back-End process; MVS access methods; Queued Sequential Access Method; Basic Direct Access Method; Basic Partitioned Access Method; PDSE processing; And now to VSAM; VSAM features; Entry Sequenced Data Set (ESDS); Key Sequenced Data Set (KSDS); Relative Record Data Set (RRDS); Catalog concepts; ICF catalogs and VTOCS; ICF catalogs (BCS); VSAM Volume Data Set (VVDS); Cluster Catalog (BCS) entries; Alternate indexes and paths.

DFSMS Constructs

Service levels for data; SCDS Base Define panel; Data Class; Defining a Data Class & its attributes; Non-VSAM Data Classes; VSAM Data Classes; Defining Management Class introduction menu; Defining Management Class panels; Storage Class Application Selection; Storage Class Define; Isolate non-SMS data; Defining a Storage Group; Defining VIO Storage Group attributes; Defining Pool Storage Group attributes; Extend Storage Groups.

Writing ACS Routines

ACS routines - what are they?; Automatic Class Selection - how many?; ACS routine rules; ACS Mask rules; ACS Read/Write variables; ACS Read-Only variables; ACS Read-Only variables - space related; ACS special purpose variables; ACS variable &ACSENVIR; Other ACS variables; OAM & tape ACS variables; ACS operations; ACS statements; Coding ACS routines; Sample MGMTCLAS routine using 'SELECT'; Sample STORCLAS routine using 'IF'; ACS application selection; ACS translation panel; ACS validation panel; Testing ACS routines; Defining test cases; ACS coding tips; Naviquest testing; Test Case Generation; ACS testing process; ACS exit routines; ACS exit steps; Programming ACS exits; ACS exit parameter structure; Actions in ACS exits; Lab exercise.

The HSM Strategy

DFSMS/MVS manuals; HSM functional overview; HSM as part of SMS; Management Class; Management Class attributes; Storage Group attributes.


Key commands; Migration types; Defining migration; Defining Primary volumes; Defining ML1 volumes; SMALLDATASETPACKING; Controlling command backup - ML1 overflow; Defining ML2 volumes; Controlling daily migration; Secondary migration - cleanup of ML1 & MCDS; Controlling migration from ML0; Migration from ML0 - Phase 1 & Phase 2; Interval migration; On-demand migration; Command migration; Transparent Cloud Tiering (TCT); Hardware Layers; Hot and cold extents; Command migration - SMS; Freevol command; Recalling datasets; Recall process; Common Recall Queue (CRQ); Enabling CRQ; Activating CRQ - SETSYS COMMONQUEUE; Controlling Recall non-SMS; Delete By Age - an alternative to migration for non-SMS; Delete if Backed Up - an alternative to migration for non-SMS; Supported datasets; Migration/Recall performance summary; SDSP performance summary; Migration volume set-up questions; Migration set-up questions.


Backup flow; Backup events; Backup volume definitions; Backup control; CDS backup; CDS backup - Point-In-Time backups; CDS recovery utility; Backup dataset naming; Backup to DASD; Command backup - volume; BACKVOL examples; Backup command; Controlling command backup - SETSYS DSBACKUP; Controlling command backup - ML1 overflow; Command backup - dataset; Backup support; Inline backup; Dataset recovery; Backup performance summary; Deleting unwanted backups; EXPIREBV DISPLAY; Backup volumes - review questions; Defining backup - review questions.

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