IBM® Information Management Software Front cover Streamline Business with Consolidation and Conversion to DB2 for z/OS Consolidate your investment in DB2 for z/OS Accelerate conversions with tools technology Adapt to industry dynamics Paolo Bruni Marcos Caurim Elise Gotay Susan Lawson Glenn McGeoch Rebecca Poole ibm.com/redbooks International Technical Support Organization Streamline Business with Consolidation and Conversion to DB2 for z/OS September 2012 SG24-8044-00 Note: Before using this information and the product it supports, read the information in “Notices” on page xv. First Edition (September 2012) This edition applies to IBM DB2 Version 10.1 for z/OS (program number 5605-DB2). © Copyright International Business Machines Corporation 2012. All rights reserved. Note to U.S. Government Users Restricted Rights -- Use, duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp. Contents Figures . ix Tables . xi Examples . xiii Notices . .xv Trademarks . xvi Preface . xvii The team who wrote this book . xvii Now you can become a published author, too! . xix Comments welcome. xix Stay connected to IBM Redbooks . xix Part 1. Introduction . 1 Chapter 1. Business considerations . 3 1.1 Historically speaking . 4 1.2 Industry dynamics driving change. 4 1.3 The reality of software conversions. 5 Chapter 2. Converting to DB2 for z/OS . 7 2.1 Converting to a relational DBMS. 8 2.2 Additional benefits of a relational DBMS. 8 2.3 Benefits of SQL . 10 2.4 Data definition language . 11 2.5 DB2 for z/OS is the platform of choice . 11 2.5.1 Scalability, availability, and usability . 12 2.5.2 Security . 13 2.5.3 Database integrity . 13 2.5.4 Continuous operation support. 14 2.5.5 Centralized catalog . 14 2.5.6 Recovery. 14 2.5.7 Usability and productivity . 15 2.5.8 Transaction manager support . 16 2.5.9 Robust Utility Suite and unlimited tools. 17 2.6 zEnterprise . 20 2.7 Additional benefits of DB2 10 for z/OS . 21 Part 2. Migration methodology . 23 Chapter 3. Application and database conversion methodology. 25 3.1 Mature application challenges on the z platform. 26 3.2 Mature application options, examples, and terminology . 27 3.2.1 Application and database conversion (manual or automated) . 28 3.2.2 Application modernization. 29 3.2.3 Application migration. 29 3.2.4 Application replacement . 29 3.2.5 Application rewrite. 29 © Copyright IBM Corp. 2012. All rights reserved. iii 3.2.6 Application re-engineering . 29 3.2.7 Migration . 30 3.2.8 Do nothing or status quo. 30 3.3 Conversion as a feasible solution . 30 3.4 Manual conversions . 32 3.4.1 Sample methods for manual conversions. 33 Chapter 4. Automated conversion methodology . 37 4.1 Conversion tool data access options . 38 4.2 Automated conversion tool projects . 39 4.2.1 Stage one: Assessment . 40 4.2.2 Stage two: Pilot . 42 4.2.3 Stage three: Conversion . 42 4.3 Data conversion guidelines . 43 4.3.1 Preparing for conversion testing . 44 4.3.2 Addressing bugs and performance issues . 45 4.3.3 Scheduling a dry run . 45 4.3.4 Planning for a backout . 45 4.4 Tool conversion strategies for 4GL programs . 46 4.4.1 The 4GL dilemma . 46 Chapter 5. Application and database conversion best practices. 47 5.1 Summary of best practices . 48 5.2 Stage one conversion planning. 50 5.2.1 Application survey and initial project sizing. 51 5.2.2 Fee-based assessment. 53 5.2.3 Options risk analysis . 54 5.3 Conversion skills and roles . 54 Chapter 6. Choosing a migration strategy . 57 6.1 Conversion strategies . 59 6.1.1 Big Bang strategy . 60 6.1.2 Loose.