IBM IMS, ESA V6 User Manual
IBM
IMS/ESA V6
Parallel Sysplex Migration Planning Guide
for IMS TM and DBCTL
Bob Gendry, Bill Keene, Rich Lewis, Bill Stillwell, Scott Chen
International Technical Support Organization
http://www.redbooks.ibm.com
SG24-5461-00
IBM
International Technical Support Organization
SG24-5461-00
IMS/ESA V6
Parallel Sysplex Migration Planning Guide
for IMS TM and DBCTL
June 1999
Take Note!
Before using this information and the product it supports, be sure to read the general information in
Appendix F, “Special Notices” on page 239.
First Edition (June 1999)
This edition applies to Version 6, Release Number 1 of IMS/ESA, Program Number 5655-158 for use with the
MVS/ESA or OS/390 operating system.
Comments may be addressed to:
IBM Corporation, International Technical Support Organization
Dept. QXXE Building 80-E2
650 Harry Road
San Jose, California 95120-6099
When you send information to IBM, you grant IBM a non-exclusive right to use or distribute the information in any
way it believes appropriate without incurring any obligation to you.
Copyright International Business Machines Corporation 1999. All rights reserved.
Note to U.S. Government Users — Documentation related to restricted rights — Use, duplication or disclosure is
subject to restrictions set forth in GSA ADP Schedule Contract with IBM Corp.
Contents
Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
Tables
Preface
The Team That Wrote This Redbook
Comments Welcome
Chapter 1. Introduction
1.1 Purpose of This Redbook
1.2 Organization of This Redbook
1.3 Prerequisite Knowledge
1.4 Assumptions
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Part 1. Developing the Plan ........................................ 3
Chapter 2. Plan Development
2.1 Planning for Migration
2.1.1 Planning Phase
2.1.2 Preparation Phase
2.1.3 Implementation Phase
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Part 2. Planning Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Chapter 3. Planning Considerations with IMS/ESA V6 in Mind
3.1 Discussing the Use of Traditional Queuing and Shared Queues
......... 13
...... 17
Chapter 4. Planning Configurations After Failures
4.1 IRLMs
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................. 19
4.1.1 Restarting Batch (DLI and DBB) Data-Sharing Jobs
4.2 IMS Subsystem Configurations
4.3 IMS Data-Sharing Subsystems
4.4 IMS Subsystems Utilizing Shared Queues
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4.5 IMS Subsystems Utilizing VTAM Generic Resources
4.6 FDBR Action After an IMS Failure
4.7 Restarting BMPs
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4.8 Degraded Mode Processing
Chapter 5. System Environment Consideration
5.1 Naming Conventions
5.2 IMS Subsystem Data Sets
5.2.1 IMS Data Sets
5.2.2 CQS Data Sets
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5.2.3 Data Set Characteristics
5.3 Executable Code
5.3.1 IMS System Code
5.3.2 CQS System Code
5.3.3 Exit Code
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5.3.4 Application Program Code
5.4 Control Blocks
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Copyright IBM Corp. 1999 iii
5.4.1 CQS Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
5.4.2 Online Access
5.5 Parameter Libraries
5.6 Dynamic Allocation
5.7 JCL Libraries
5.7.1 Procedures
5.7.2 Jobs
....................................... 34
5.7.3 DBRC JCL Libraries
5.8 Making the Decision
5.8.1 Data Sets That Must Be Unique
5.8.2 Data Sets That Must Be Shared
5.8.3 Data Sets That Are Probably Shared
5.8.4 Data Sets That Are Probably Unique
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
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Chapter 6. Applications and Databases
6.1 Applications
6.2 Databases
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6.3 Partitioned Applications and Databases
6.4 Cloned Applications and Data Sets
6.5 Handling Databases That Are Not Shared
6.5.1 Routing Transactions
6.5.2 Copying Databases
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
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Part 3. Planning Considerations for IMS TM ........................... 45
Chapter 7. Introduction to IMS TM Considerations
7.1 Overview
7.2 IMS TM Configuration Considerations
7.2.1 Cloning
7.2.2 Joining
7.2.3 Front-End and Back-End
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Chapter 8. IMS TM Network Considerations
8.1 Overview
8.2 Special Network Considerations
8.2.1 SLUTYPEP
8.2.2 ISC
8.3 APPC (LU 6.2)
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8.4 ETO Considerations with Shared Queues
8.4.1 Duplicate Terminal Names
8.4.2 Solutions
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
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8.4.3 Limiting the Number of End-User Signons
8.4.4 Dead Letter Queue Considerations
8.5 Conversational Transaction Processing
8.6 Application Program Considerations
8.7 Application Affinities
8.8 IMS APPLIDs
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
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8.9 VTAM Model Application Program Definitions
8.10 A Model Application Program Definition Example
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Chapter 9. IMS TM Workload Balancing Considerations
9.1 Overview.
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9.2 Network Workload Balancing
9.2.1 Instructions to the End-Users
iv IMS Parallel Sysplex Migration Planning Guide
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9.2.2 USSTAB Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
9.2.3 CLSDST PASS VTAM Application Program
9.2.4 USERVAR Processing
9.2.5 Use of VTAM Generic Resources
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
...................... 69
9.2.6 VTAM Generic Resources for APPC/IMS
9.2.7 Printers and Network Workload Balancing
9.2.8 Network Workload Balancing With Session Managers
9.2.9 Network Workload Balancing With TCP/IP and TN3270
9.3 Application Workload Balancing
9.3.1 Network Workload Balancing
9.3.2 MSC Balancing
9.3.3 IMS Workload Router
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
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9.3.4 Shared Queues and Application Workload Balancing
9.4 Transaction Scheduling Considerations
9.5 Summary of Workload Balancing Considerations
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Chapter 10. IMS TM System Definition Considerations
10.1 Master Terminals With IMS/ESA Version 5
10.2 Master Terminals With IMS/ESA Version 6
10.3 Security
10.4 Resource Definitions and Usage
10.5 MSC Considerations
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
........................ 89
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10.5.1 Inter-IMSplex MSC Without Shared Queues
10.5.2 Migration to Shared Queues
........................ 91
10.5.3 Example: Migration of Two MSC-Connected Systems
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10.5.4 Example: MSC Link from a Shared Queues Group Member to a
Remote IMS
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10.5.5 Example: MSC Link Between Members of Two Shared Queues
Groups
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10.5.6 Example: Multiple MSC Links between Members of Two Shared
Queues Groups
10.5.7 Example: Backup MSC Link Configuration
10.6 Serial Transactions
10.6.1 Serial Transactions With Traditional Queuing
10.6.2 Serial Transactions With Shared Queues
10.7 Undefined Destinations
10.7.1 Destination Determination
10.7.2 Back-End Processing of Input Transactions
10.7.3 Comments and Recommendations
10.8 Online Change
10.9 SPOOL Terminals
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Part 4. Data-Sharing and Shared Queues Considerations .................. 107
Chapter 11. Data-Sharing Enablement
11.1 IMS System Definition
11.2 IRLM
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11.2.1 IRLM Subsystem Names
11.2.2 IRLM as Lock Manager
11.2.3 IRLM Scope
11.3 DBRC
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11.3.1 SHARECTL
11.3.2 SHARELVL
11.3.3 Skeletal JCL
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Contents v
11.4 Database Data Set Sharability ........................ 112
11.4.1 VSAM SHAREOPTION(3 3)
11.4.2 DISP=SHR in JCL or DFSMDA
11.5 CFNAMES Statement
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11.6 DEDB Statements in the DFSVSMxx Member
11.7 Order of Implementation Steps
11.8 IMS Procedures for Data-Sharing
11.9 Data-Sharing Performance Considerations
11.10 Sources of Performance Information
11.11 Data Sharing Coupling Facility Performance Impacts
11.11.1 IRLM CF Access
11.11.2 IMS CF Access
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Chapter 12. Shared Queues Enablement
12.1 Program Properties Table
12.2 Structure Definitions
12.3 Log Stream Definitions
12.4 System Checkpoint Data Sets
12.5 Structure Recovery Data Sets
12.6 CQS Procedure
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12.7 BPE Configuration PROCLIB Member
12.8 CQS Initialization Parameters PROCLIB Member (CQSIPxxx)
12.9 CQS Local Structure Definition PROCLIB Member (CQSSLxxx)
12.10 CQS Global Structure Definition PROCLIB Member (CQSSGxxx)
12.11 Security for CQS Structures
12.12 ARM Policy Updates
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12.13 IMS Shared Queues PROCLIB Member (DFSSQxxx)
12.14 QMGR and Shared Queues Traces
12.15 IMS Procedure
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12.16 IMS Procedures for Shared Queues
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Part 5. MVS Parallel Sysplex Conderations ............................ 129
Chapter 13. VTAM Generic Resources Enablement
13.1 VTAM Requirements
13.2 IMS Requirements
13.3 APPC/IMS Requirements
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Chapter 14. Automatic Restart Manager (ARM)
14.1 Exceptions to Automated Restarts of IMS
14.2 Restart Conditions
14.3 Restart Groups
14.4 Other ARM Capabilities
14.5 ARM with IRLM
14.5.1 Restarting after IRLM Abends
14.5.2 Restarting after System Failures
14.6 ARM with CQS
14.7 ARM with FDBR
14.8 Information for ARM Policies
Chapter 15. Coupling Facility
15.1 Coupling Facility Planning Guidelines
15.1.1 Structure Placement Rules
15.1.2 Initial Structure Placement
vi IMS Parallel Sysplex Migration Planning Guide
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15.1.3 Structure Sizing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
15.1.4 IMS Database Manager
15.1.5 IRLM
15.1.6 Shared Queues
..................................... 146
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15.1.7 Summary of Structure Characteristics
15.2 Changing CF Structure Sizes
15.2.1 Connection and Structure Persistence
15.2.2 IMS Buffer Invalidation Structure Changes
15.2.3 DEDB VSO Cache Structure Changes
15.2.4 IRLM Lock Structure Changes
15.2.5 Automatic Rebuilds
15.2.6 Shared Queues Structure Changes
15.2.7 Alter and Rebuild for Shared Queues Structures
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Part 6. Operation Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Chapter 16. IMS Connections, Security and User Exits
16.1 IMS Connections
16.2 Security
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
16.2.1 RACF Security
16.3 IMS SMU Security
16.4 Database Data Set Dispositions
16.5 User Exits
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
16.5.1 IMS System Exits
16.5.2 IMS Database Manager Exits
16.5.3 IMS Transaction Manager Exits
16.5.4 Common Queue Server Exit Routines
Chapter 17. IMS and User JCL
17.1 IMS Procedures
17.1.1 Started Procedures
17.1.2 Executed Procedures
17.2 IMS Jobs
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
17.3 DBRC Skeletal JCL
17.4 Other Backup and Recovery JCL
17.5 Other Application JCL
17.6 BMP JCL
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
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17.6.1 Using the Function Delivered by APAR PQ21039
17.6.2 The IMSGROUP Function
......................... 174
17.6.3 Handling IMSID Without APAR PQ21039 Function
17.6.4 Maintenance Levels of RESLIB
17.6.5 Routing BMP Jobs
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Chapter 18. Operations
18.1 Operational Procedures
18.2 Automated Operations
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
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18.2.1 IMS Time-Control Operations
18.2.2 IMS AO Exits
18.2.3 Other AO Products
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18.3 Use of IRLM SCOPE=NODISCON
18.3.1 Use of RDI Regions
18.4 Recovery Procedures
18.5 Support Procedures
18.6 IMS Log Management
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Contents vii
18.6.1 IMS Log Archive .............................. 183
18.7 Job Scheduling Procedures
18.8 Online Change Procedures
18.9 IMS Commands from MVS Consoles
18.9.1 GLOBAL Commands
18.9.2 Alternative to GLOBAL Commands
18.9.3 Recommendations for IMS Commands From MVS Consoles
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... 187
Chapter 19. Fast Database Recovery (FDBR)
19.1 FDBR Monitoring
19.1.1 Log Monitoring
19.1.2 XCF Status Monitoring
19.2 Invoking Recovery
19.3 FDBR Failures
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
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19.4 Restarting IMS after FDBR Completion
19.5 DBRC Authorizations with FDBR
19.6 ARM and FDBR
................................. 192
19.6.1 ARM Support for IMS With FDBR Active
19.6.2 ARM Support for FDBR
19.7 FDBR, XRF, and ARM
.......................... 193
.............................. 193
19.7.1 FDBR Advantages and Disadvantages
19.7.2 XRF Advantages and Disadvantages
19.7.3 ARM Advantages and Disadvantages
19.8 Recommendations
Chapter 20. Recovery Procedures
20.1 Image Copies
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
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20.1.1 Database Image Copy (DFSUDMP0)
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20.1.2 Concurrent Image Copy (DFSUDMP0 with CIC Option)
20.1.3 Online Database Image Copy (DFSUICP0)
20.1.4 Database Image Copy 2 (DFSUDMT0)
20.1.5 Summary of Image Copies
20.2 Database Recoveries
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
........................ 198
20.2.1 Time-Stamp Recovery Considerations
20.3 IMS Batch (DBB and DLI) Job Abends
20.4 IMS Online (TM or DBCTL) Abends
20.5 IRLM Abends
20.6 MVS Failures
20.7 Lock Structure Failures
................................... 200
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20.8 OSAM and VSAM Structure Failures
20.9 DEDB VSO Structure Failures
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20.9.1 Procedure for Failure of One of Two Structures
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20.9.2 Procedure for Failure of Only Structure or Both Structures
20.10 CF Connection Failures
20.11 CF Connection Failure to Lock Structure
............................ 203
................. 203
20.12 CF Connection Failure to an OSAM or VSAM Structure
20.13 CF Connection Failure to a DEDB VSO Structure
............ 204
20.13.1 Procedure with Connectivity to a Second Structure
20.13.2 Procedure without Connectivity to a Second Structure
20.14 Disaster Recovery
20.14.1 Image Copy Only Disaster Recovery
20.14.2 Time-Stamp Recovery Disaster Recovery
20.14.3 Latest Archived Log Disaster Recovery
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
................. 205
.............. 206
............... 206
20.14.4 Real-Time Electronic Log Vaulting Disaster Recovery
....... 197
.... 203
......... 204
........ 205
...... 205
....... 207
viii IMS Parallel Sysplex Migration Planning Guide
Appendix A. Naming Convention Suggestions .................. 209
Appendix B. IMS System Data Sets
B.1 Data Sets That Must Be Unique
B.2 Data Sets That Must Be Shared
B.3 Data Sets That Are Probably Unique
B.4 Data Sets That Are Probably Shared
........................ 215
........................ 215
........................ 216
..................... 216
..................... 216
Appendix C. Sample USERVAR Exit for Network Balancing
Appendix D. Parallel Sysplex Publications
Appendix E. Migration Plan Task List
E.1 Planning Phase
E.2 Preparation Phase
E.3 Implementation Phase
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
E.3.1 Data Sharing Environment Implementation
E.3.2 Generic Resources Environment Implementation
E.3.3 Shared Queues Environment Implementation
E.3.4 Implementation of Second System (Clone)
Appendix F. Special Notices
Appendix G. Related Publications
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
. . . . . . . . . . . . . . . . . . . . . . . . . 241
.................... 231
....................... 233
............... 237
........... 237
............. 238
............... 238
G.1 International Technical Support Organization Publications
G.2 Redbooks on CD-ROMs
G.3 Other Publications
............................. 241
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241
.......... 219
........ 241
How to Get ITSO Redbooks
IBM Redbook Fax Order Form
Glossary
List of Abbreviations
Index
ITSO Redbook Evaluation
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
................................. 249
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
............................... 253
............................. 243
............................ 244
Contents ix
x IMS Parallel Sysplex Migration Planning Guide
Figures
1. Using Unique IRLM Names and Moving IRLMs . . . . . . . . . . . . . . . 20
2. Using Unique IRLM Names and Changing IRLMs Used by IMSs
3. Using ″IRLM″ for all IRLM Names
. . . . . . . . . . . . . . . . . . . . . . . 21
4. Using One Instance of a Session Manager Without ISTEXCGR
5. Using One Instance of a Session Manager With ISTEXCGR
6. Placing the Session Manager on an MVS Without IMS
7. Session Managers With Generic Resource Support
8. Using DNS With TN3270 and VTAM GR
9. Using DNS With TN3270 and VTAM GR
. . . . . . . . . . . . . . . . . . . . 79
. . . . . . . . . . . . . . . . . . . . 80
. . . . . . . . . . . 78
. . . . . . . . . . . . 78
10. Using DNS With TN3270 and VTAM GR After a Failure of IMS1
11. Two IMS systems With an MSC connection
12. Migration of IMSB to a Shared Queues Group
................. 95
................ 96
13. Migration of IMSA and IMSB to a shared queues group is completed
14. MSC link from shared queues group member to remote IMS
15. MSC links between members of two shared queues groups
. . . . . 21
. . . . . . 77
........ 77
...... 81
. 96
....... 98
....... 99
16. MSC connections from shared queues group members to remote IMS
systems
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
17. Backing up logical links from a shared queues group to a remote IMS 101
18. Starting a backup link to a shared queues group
............. 101
Copyright IBM Corp. 1999 xi
xii IMS Parallel Sysplex Migration Planning Guide
Tables
1. IMS Online Region Library . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
2. IMS Procedures Summary
3. IMS Shared Queues Procedure Parameters
4. ARM Element Terms
5. Structure Characteristics
6. Summary of IMS Connectors
7. IMSID Usage Before Cloning
8. IMSID Usage After Cloning
9. Image Copy With Concurrent Updates
10. Task List
11. Task List
12. Task List
13. Task List
14. Task List
15. Task List
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
. . . . . . . . . . . . . . . . . . . . . . . . . . . 116
. . . . . . . . . . . . . . . . 128
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
. . . . . . . . . . . . . . . . . . . . . . . . . . . 150
. . . . . . . . . . . . . . . . . . . . . . . . . 159
. . . . . . . . . . . . . . . . . . . . . . . . . 174
. . . . . . . . . . . . . . . . . . . . . . . . . . 174
. . . . . . . . . . . . . . . . . . . 198
Copyright IBM Corp. 1999 xiii
xiv IMS Parallel Sysplex Migration Planning Guide
Preface
This redbook provides information for those planning for migrating IMS/ESA 6.1
system to a Parallel Sysplex environment using data sharing and shared queues.
The redbook lists all important factors to be consider during the planning stage.
It also lists important features and describes the relationships between IMS/ESA
V6 and OS/390. Readers will, therefore, be able to understand what benefits can
be derived even before the complete implementation to the Parallel Sysplex
environment.
The target audience is customer IT architects, system designers, IT managers
and IBM representatives who are helping customers on migration projects.
The Team That Wrote This Redbook
This redbook was written by a team of IMS specialists from the IMS Advanced
Technical Support Department at the IBM Dallas Systems Center.
Bob Gendry has been a member of the IMS Advanced Technical Support
Department at the IBM Dallas Systems Center since 1978 and has over 25 years
of experience in providing technical support for IMS. He has given multiple
presentations on IMS-related topics to user groups and at the IMS Technical
Conferences in the United States and Europe. He has provided assistance to
multiple IMS users in planning and implementating IMS in a Parallel Sysplex
environment for the past several years. In addition, he has prepared and taught
educational materials directly related to the understanding, implementation, and
use of IMS in a Parallel Sysplex environment.
Bill Keene was a member of the IMS Advanced Technical Support team at the
IBM Dallas Systems Center. He has over 25 years of experience in providing
technical support for IMS. He is a frequent speaker at GUIDE, SHARE, and IMS
Technical Conferences on IMS-related topics. He has provided assistance to
multiple IMS users in planning for and implementing the use of IMS in a Parallel
Sysplex environment for the past several years. In addition, he has prepared
and taught educational materials directly related to the understanding,
implementation, and use of IMS in a Parallel Sysplex environment.
After contributing to this redbook, Bill Keene retired from IBM.
Rich Lewis has been a member of the IMS Advanced Technical Support
Department at the IBM Dallas Systems Center since 1979. He has over 25 years
of experience in providing technical support for IMS. Since the introduction of
Parallel Sysplex, he has been assisting users in implementing IMS data-sharing.
He has written technical documents, created presentations, and developed an
IMS Parallel Sysplex data sharing course. He has provided planning services to
many customers for the introduction of IMS into their Parallel Sysplex
environments. Rich regularly presents Parallel Sysplex topics at IMS Technical
Conferences and user group meetings in the United States and Europe.
Bill Stillwell has been providing technical support and consulting services to IMS
customers as a member of the Dallas Systems Center for 17 years. During that
time, he developed expertise in application and database design, IMS
Copyright IBM Corp. 1999 xv
performance, fast path, data sharing, planning for IMS Parallel Sysplex
exploitation and migration, DBRC, and database control (DBCTL).
He also develops and teaches IBM Education and Training courses, including
IMS/ESA Version 6 Product Enhancements, IMS Shared Queues, and IMS Fast
Path Implementation, and is a regular speaker at the annual IMS Technical
Conferences in the United States and Europe.
Scott Chen is a member of International Technical Support Organization, San
Jose Center. Scott has installing, configuring, debugging, tuning, consulting,
application designing, programming and studying MVS and OS/390 internal,
database and transaction management system (includes IMS) and digital library
softwares for over 25 years.
Thanks to the following people for their invaluable contributions to this project:
Dick Hannan
IBM Santa Teresa Laboratory
IMS Development
Comments Welcome
Your comments are important to us!
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comments about this or other redbooks in one of the following ways:
•
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•
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xvi IMS Parallel Sysplex Migration Planning Guide
Chapter 1. Introduction
1.1 Purpose of This Redbook
This redbook provides information for those creating a plan for migrating an
IMS/ESA 6.1 system to a Parallel Sysplex environment using data sharing and
shared queues. The reader is assumed to be familiar with the requirements for
data sharing and shared queues implementation. This information may be
obtained from the IBM Education and Training classes for IMS/ESA Block Level
Data Sharing, Shared Queues, and IMS/ESA Version 6 and from IMS/ESA Data
Sharing in a Parallel Sysplex, SG24-4303.
The redbook applies to both IMS/ESA TM and Database Control (DBCTL) users.
Some Parallel Sysplex functions and facilities, such as Shared queues, apply
only to IMS Transaction Manager (TM) users. Sections of this redbook which
apply only to IMS TM users or only to DBCTL users are identified.
1.2 Organization of This Redbook
The main body of this redbook is divided into six sections plus several
appendices.
1. Developing the Plan
This section addresses the plan itself, including the purpose of the plan, its
content, and the migration tasks that should be identified within the plan.
2. Planning Considerations
This section addresses some of the general technical issues that must be
considered when developing and implementing the plan and is intended to
help make decisions.
3. Planning Considerations for IMS TM
This section focuses on technical issues related to the IMS TM environment.
4. Data Sharing and Shared Queues Considerations
This section reviews some technical issues related to IMS data sharing and
shared queues.
5. MVS Parallel Sysplex Considerations
Here, we look at some technical topics related to IMS interact with MVS
Parallel Sysplex.
6. Operation Considerations
Finally, we review technical topics related to IMS operation and recovery
procedures.
7. Appendixes
The appendixes provide additional technical information that might be useful
in performing some of the tasks. A sample list of tasks is included at the
end of this redbook in Appendix E, “Migration Plan Task List” on page 233.
This list includes references to the parts of this redbook that apply to each
task in the list.
Copyright IBM Corp. 1999 1
A list of useful Parallel Sysplex publications, other than the standard
IMS/ESA V6.1 product publications, is provided in Appendix D, “Parallel
Sysplex Publications” on page 231.
1.3 Prerequisite Knowledge
This redbook is written for those who are familiar with the following:
•
IMS block-level data sharing definition requirements for IMS, IRLM, and the
Coupling Facility
•
IMS shared queues definition requirements for IMS (including the Common
Queue Server) and the Coupling Facility
•
Recovery procedures for failures in the IMS block-level data sharing
environment
•
Recovery procedures for failures in the shared queues environment
•
Roles of IRLM and the Coupling Facility in supporting block-level data
sharing
•
Roles of the Common Queue Server and the Coupling Facility in supporting
shared queues
1.4 Assumptions
The assumptions about the installation for which the plan is being developed
are:
•
The installation is in production with IMS/ESA V6.1 prior to the
implementation of this plan.
•
A Parallel Sysplex environment has been implemented prior to the
implementation of this plan.
•
The application (system) to be migrated has been identified.
•
The existing IMS environment and its applications are to be cloned.
There is only one current IMS system to be cloned. Its workload will be split
across multiple IMS systems which are as identical in function as possible.
They can have different workload capacities.
2 IMS Parallel Sysplex Migration Planning Guide
Part 1. Developing the Plan
Copyright IBM Corp. 1999 3
4 IMS Parallel Sysplex Migration Planning Guide
Chapter 2. Plan Development
This section addresses the development of the migration plan and identifies
some of the steps and considerations you might encounter when developing the
plan. The result of this exercise is not to ″perform″ any of the implementation
tasks but to identify those tasks which must be done and to create a plan for
accomplishing them. For example, the plan can identify as a task the
establishment of a naming convention for system data sets. The naming
convention itself is not a part of the plan, but is a result of implementing the
plan.
2.1 Planning for Migration
The process of migrating to an IMS data sharing and/or shared queues Parallel
Sysplex environment should be accomplished in three phases: a planning phase,
a preparation phase, and an implementation phase.
2.1.1 Planning Phase
The purpose of this phase is to identify/document where you are coming from,
where you are going, what you will do if there are failures, and to determine how
the plan will be created, who has responsibility, what will be its content and
format, what planning or project management tools will be used, and finally to
develop the plan itself.
Below, we have identified four major steps in the planning phase. You might
recognize fewer or more, but each step below has a purpose, and that purpose,
must be satisfied in any planning process.
2.1.1.1 Understand the Existing Environment
The first step in the planning phase is to understand the existing environment.
This includes knowing, for each application, the resource requirements (such as,
CPU, I/O), service level requirements, schedules and workloads, connections to
other subsystems, and the reasons for migrating (for instance, reduced costs or
improved performance, capacity, or availability). You should also identify any
″inhibitors″ to migration, such as non-sharable resources.
The assumption here is that the target environment is replacing an existing
environment for one or more reasons (for example, capacity, performance,
availability, flexibility,...). However, the target environment must continue to
provide the equivalent function with performance and availability at least as
good as the existing environment. So, in order to define a target environment
which will do this, it is first necessary to understand the existing environment.
The following describes the characteristics of the existing environment that
should be known before defining the target.
•
Why are you migrating to this environment?
A major part of developing a migration plan is to choose the configuration to
which the migration will be done. This configuration is affected by the
reasons for making the migration. The migration to IMS data sharing and
shared queues with Parallel Sysplex can be used to provide multiple
benefits. These include, but are not limited to:
− Increased availability
Copyright IBM Corp. 1999 5
− Increased capacity
− Incremental growth capability
− Operational flexibility
•
What is the current workload?
This should be documented in terms that will facilitate the distribution of that
workload over two or more (perhaps) processors and should include
transaction volumes as well as batch/BMP and support jobs such as image
copies, reorganizations, and so forth.
•
Who are the heavy resource users?
Which of the above transactions or batch processes require the greatest
number of, CPU or I/O resources, and which transactions are the highest
volumes. It might be necessary to make special provisions for them in the
target environment.
•
What are the service level commitments?
What agreements exist for transaction response times, batch elapsed times
and availability? Are users billed according to the resources they use?
•
To what systems is the existing IMS connected?
This should include other IMSs, DB2s, CICSs, and any other ″intelligent″
systems or devices that might be sensitive to the identity of the IMS system
to which they are connected.
•
What are the online and batch schedules?
What are the hours of availability for online access and what is the ″batch
window″ (if there is one)?
•
Are there any batch or online dependencies?
Are there ″sequences″ of processes that must be maintained in the target
environment. For example, transactions defined as SERIAL, implying a FIFO
processing sequence, should be identified.
•
Are any user exits sensitive to the identity of the IMS system on which they
execute?
Look particularly at transaction manager exits and system exits as there will
be multiple transaction managers with different IDs, connected, perhaps, to
different subsystems (for instance, different CICSs or different DB2s) and with
only part of the original network.
•
Do any user-written programs process the IMS logs?
The logs will be quite different, with each log containing only part of the
information that was on the original single-image log.
•
What are the business-critical applications?
If one component of the target environment fails (for instance, one of two IMS
systems) and can′t be immediately restarted, it might be necessary to
quiesce relatively unimportant work on the surviving system in order to shift
the entire critical workload to that system. It might also be necessary to shift
part (or all) of the network to the surviving system.
•
Are there any non-sharable resources?
6 IMS Parallel Sysplex Migration Planning Guide
An installation can choose not to share some databases. (See 6.5, “Handling
Databases That Are Not Shared” on page 42). These must be identified and
plans made for their migration to the target system.
2.1.1.2 Define Target Environment
The next step in the migration planning phase is to define the configuration of
the target environment. This includes the number of IMS subsystems in the data
sharing group, shared queues group, VTAM generic resource group, the MVS
system on which each IMS will run, other subsystems outside of the Parallel
Sysplex environment to which the target IMS will connect ( for example, other
IMSs, CICS, DB2), the coupling facilities to be used, and which systems will be
used for various purposes. For example, one must know on which systems IMS
BMPs will be run, or if applications are to be partitioned, on which systems they
will run. Be sure the target environment satisfies the reasons for migration.
The elements of the target configuration include the following:
•
MVS Systems
The MVS systems in the target configuration should be identified by the
processors and LPARs on which they run and the types of work they will
support. The types of work include the IMS subsystems and support
processes they will handle.
•
IMS Subsystems and Processes
These are IMS online systems (either IMS Transaction Manager, DCCTL, or
DBCTL), IMS batch jobs, and IMS support processes. Support processes
include database image copies, database reorganizations, log archiving, and
definition jobs. The MVS systems on which they will run should be identified.
The use of each IMS online system should be identified.
− IMS TM
For IMS TM this includes the terminal networks that will use them, the
ISC and MSC connections to other systems, APPC connections, the
associated DB2 subsystems, the application programs, and transactions
that will run on each system. Application programs include BMPs.
For IMS TM and DCCTL subsystems, special planning considerations will
be required if shared queues, VTAM generic resources, and/or other
Parallel Sysplex enhancements delivered with IMS/ESA V6.1 are to be
used.
− DBCTL
For DBCTL this includes the CICS systems that will attach to them, the
DB2 systems used by BMPs, and the application programs that will run
on each system. Application programs include BMPs.
For cloned systems, it is assumed that all online transactions and programs
will be run on each system. For performance, operational, or affinity
reasons, there may be exceptions. These should be understood, and the
target configuration must account for these considerations. Typically, BMPs
and IMS batch jobs will be directed to particular IMS or MVS systems. Many
installations will want to run them on only one MVS system.
•
Coupling Facilities
Chapter 2. Plan Development 7
The coupling facilities and coupling facility structures to support IMS should
be identified. This includes structure sizes and the placement of these
structures in support of:
− Data sharing structures
- IRLM (lock structure)
- VSAM buffer invalidation structure (directory-only cache structure)
- OSAM buffer invalidation/cache structure (store-through cache
structure)
- Shared DEDB VSO structure(s) (store-in cache structure)
− Shared Queues
- Message queue and EMH queue primary and overflow structures (list
structures)
- MVS logger structures (list structures)
− VTAM Generic Resource structure (list structure)
2.1.1.3 Define Degraded Mode Environment
Next you must decide what you will do if something fails. Since a Parallel
Sysplex consists of multiple MVS and IMS systems, an installation should plan
what it will do if one or more components fail. For example, there may be
certain applications or systems that are more critical to the business and
therefore should have preference to be available when there is an outage of part
of the system. This is called degraded mode processing.
During this phase, you should determine both the processing and business
impact of the failure of any component of the target environment. Identify those
applications which must be given priority in a degraded processing environment.
You must also consider what users who are connected to a failed component
should do (such as, log on to another IMS?).
Some tasks which should be included in this phase are:
•
Perform a ″component failure impact analysis (CFIA)″ for critical components
•
Prioritize applications for degraded mode processing
•
Identify applications to run in degraded mode
•
Identify network terminals and connections to be reconnected to another
system if one system fails
2.1.1.4 Develop the Plan
The plan should recognize the following two phases of the migration process:
preparation and implementation. Although this document does not prescribe a
format for the migration plan, the following elements should be included:
•
Tasks - What must be done?
•
Responsibility - Who is responsible to see that it gets done?
•
Dependencies - Is any task a prerequisite to another task?
•
Duration - How long should each task take?
•
Schedule - When must it be done - start/complete/drop-dead dates?
•
Status - A mechanism for monitoring progress?
8 IMS Parallel Sysplex Migration Planning Guide
Appendix E, “Migration Plan Task List” on page 233 is a list of tasks that have
been identified which should be a part of the migration plan.
2.1.2 Preparation Phase
Most of the tasks identified in the migration plan are implemented during the
preparation phase. The plan may say, for example, that a naming convention
must be established for system data sets. During this phase, that naming
convention will be developed. Or the plan may say that operational procedures
must be updated. During this phase, those procedures are updated.
Some of the tasks in this phase will be ″decision″ type tasks (for instance, how
many copies of RESLIB do I want?). Others will be ″implementing″ some of
these decisions (such as, making two copies of RESLIB). At the conclusion of
this phase, you are ready to migrate your existing system to production.
2.1.3 Implementation Phase
The final phase in the migration process is the actual implementation. That is,
the existing environment will be converted to an operational IMS Parallel
Sysplex environment. The actual ″implementation plan″ will probably be
produced as part of the preparation phase as it is unlikely that enough
information will be available during planning to generate this plan.
Chapter 2. Plan Development 9
10 IMS Parallel Sysplex Migration Planning Guide
Part 2. Planning Considerations
Copyright IBM Corp. 1999 11
12 IMS Parallel Sysplex Migration Planning Guide
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