IBM Software Group | IMS Information Management Software              IBM Software Group            IMS Information Manage...
IBM Software Group | IMS Information Management SoftwareTopics Covered  Operating System Access Methods  Origins of OSAM...
IBM Software Group | IMS Information Management Software              Operating System Access MethodsVirtual Storage Acces...
IBM Software Group | IMS Information Management Software         VSAM Versus OSAM for Data Set GroupsThe choice between OS...
IBM Software Group | IMS Information Management Software                                      San Ramon User’s Group - Oct...
IBM Software Group | IMS Information Management Software                                      San Ramon User’s Group - Oct...
IBM Software Group | IMS Information Management Software                                      San Ramon User’s Group - Oct...
IBM Software Group | IMS Information Management Software                                      San Ramon User’s Group - Oct...
IBM Software Group | IMS Information Management Software                                      San Ramon User’s Group - Oct...
IBM Software Group | IMS Information Management Software                                      San Ramon User’s Group - Oct...
IBM Software Group | IMS Information Management Software                                      San Ramon User’s Group - Oct...
IBM Software Group | IMS Information Management Software                                      San Ramon User’s Group - Oct...
IBM Software Group | IMS Information Management Software                                      San Ramon User’s Group - Oct...
IBM Software Group | IMS Information Management Software                                      San Ramon User’s Group - Oct...
IBM Software Group | IMS Information Management Software        Implementing OSAM CF Caching You can implement OSAM cachi...
IBM Software Group | IMS Information Management Software     IBM Software Group            IMS Information Management Soft...
IBM Software Group | IMS Information Management Software       HALDB (High Availability Large Database) High Availability...
IBM Software Group | IMS Information Management Software                           HALDB Highlights OSAM and VSAM (ESDS a...
IBM Software Group | IMS Information Management Software                  HALDB Database Data Sets Each HALDB database ha...
IBM Software Group | IMS Information Management Software                            HALDB OverviewDatabase candidates for ...
IBM Software Group | IMS Information Management Software          IBM Software Group            IMS Information Management...
IBM Software Group | IMS Information Management Software        VSAM to OSAM Conversion ConsiderationsPlanning:1.   Buffer...
IBM Software Group | IMS Information Management Software       VSAM to OSAM Conversion ConsiderationsConversion:1.   IC th...
IBM Software Group | IMS Information Management Software       VSAM to OSAM Conversion ConsiderationsConversion (cont.):6....
IBM Software Group | IMS Information Management Software        VSAM to OSAM Conversion ConsiderationsConversion (cont.):8...
IBM Software Group | IMS Information Management Software       VSAM to OSAM Conversion ConsiderationsSystem changes:1.   M...
IBM Software Group | IMS Information Management Software         Example of Allocating an OSAM Data Set //OSAMALLO JOB A,O...
IBM Software Group | IMS Information Management Software                                      San Ramon User’s Group - Oct...
IBM Software Group | IMS Information Management Software               IBM Software Group          IMS Information Managem...
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OSAM – The Healthy Alternative to VSAM - IMS UG October 2012 San Ramon

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OSAM – The Healthy Alternative to VSAM - IMS UG October 2012 San Ramon

  1. 1. IBM Software Group | IMS Information Management Software IBM Software Group IMS Information Management SoftwareOSAM – “The HealthyAlternative to VSAM”Charles JonesIMS Database SupportSilicon Valley Laboratorycharles@us.ibm.comOctober 18, 2012 San Ramon Users Group -Ramon User’s18 - Oct. 18 San October Group © Copyright IBM Corporation 2012 © Copyright IBM Corporation 2012
  2. 2. IBM Software Group | IMS Information Management SoftwareTopics Covered  Operating System Access Methods  Origins of OSAM  Sequential Buffering  OSAM Caching in CF (Coupling Facility) OSAM and HALDB  VSAM to OSAM Conversion Considerations San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  3. 3. IBM Software Group | IMS Information Management Software Operating System Access MethodsVirtual Storage Access Method (VSAM)IBM uses two available VSAM access methods: 1) Key-Sequenced Data Sets (KSDS) are used for index and HISAM databases 2) Entry-Sequenced Data Sets (ESDS) are used for the primary data sets for HDAM, HIDAM, PHDAM, and PHIDAM databases.VSAM data sets are defined using the VSAM Access Method Services (AMS)Utility program.Overflow Sequential Access method (OSAM)OSAM is unique to IMS, is delivered as part of the IMS product, and consistsof a series of channel programs that IMS executes to perform I/O.OSAM data sets are defined using JCL statements. San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  4. 4. IBM Software Group | IMS Information Management Software VSAM Versus OSAM for Data Set GroupsThe choice between OSAM and VSAM ESDS for the primary databasedata sets depends on: - whether your site already uses VSAM - whether you need to use the features of OSAMThe reasons you might want to use OSAM include: - The availability of Sequential Buffering - The structural limit on the amount of data that IMS can store in a VSAM ESDS (4 GB) versus OSAM (8 GB) - OSAM reduced CPU cost (shorter instruction path)You can change a database from one access method to the other byunloading the database, changing and regenerating the DBD, thenreloading the database. San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  5. 5. IBM Software Group | IMS Information Management Software San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  6. 6. IBM Software Group | IMS Information Management Software San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  7. 7. IBM Software Group | IMS Information Management Software San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  8. 8. IBM Software Group | IMS Information Management Software San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  9. 9. IBM Software Group | IMS Information Management Software San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  10. 10. IBM Software Group | IMS Information Management Software San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  11. 11. IBM Software Group | IMS Information Management Software San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  12. 12. IBM Software Group | IMS Information Management Software San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  13. 13. IBM Software Group | IMS Information Management Software San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  14. 14. IBM Software Group | IMS Information Management Software San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  15. 15. IBM Software Group | IMS Information Management Software Implementing OSAM CF Caching You can implement OSAM caching by means of the CO (Cache Option) parameter in IOBF control statement on DFSVSMxx of IMS.PROCLIB. Different caching options may be defined for each OSAM subpool. Omitted - No data caching. Caching is not active for the subpool. N - No data caching. Caching is not active for the subpool. A - Cache all data. Write all data read from DASD and all changed data to the CF. C - Cache only changed data. Write all changed data written to DASD to the CF. If you specify any value other than A, C, or N, no data caching for the subpool occurs. The default is N. San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  16. 16. IBM Software Group | IMS Information Management Software IBM Software Group IMS Information Management SoftwareOSAM and HALDB A Dynamic Duo San Ramon Users Group -Ramon User’s18 - Oct. 18 San October Group © Copyright IBM Corporation 2012 © Copyright IBM Corporation 2012
  17. 17. IBM Software Group | IMS Information Management Software HALDB (High Availability Large Database) High Availability Database  Partition independence • Allocation, authorization, reorganization, recovery by partition Self healing pointers  Reorganization of partition does not require changes to secondary indexes or logically related databases Large Database  Databases are partitioned • Up to 1001 partitions per database • Partitions have up to 10 data set groups San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  18. 18. IBM Software Group | IMS Information Management Software HALDB Highlights OSAM and VSAM (ESDS and KSDS) supported Partition selection is done by key range or user exit Logical relationships and secondary indexes supported  Secondary indexes may be partitioned DBRC is required  Databases must be registered Dynamic allocation uses DBRC information  DFSMDA is not used San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  19. 19. IBM Software Group | IMS Information Management Software HALDB Database Data Sets Each HALDB database has up to 1001 partitions PHIDAM has index, ILDS, up to 10 data set groups per partition  3 to 12 data sets per partition  3 to 12,012 data sets per database PHDAM has ILDS and up to 10 data set groups per partition  2 to 11 data sets per partition  2 to 11,011 data sets per database PSINDEX has no ILDS or data set groups  1 data set per partition  1 to 1001 data sets per secondary index San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  20. 20. IBM Software Group | IMS Information Management Software HALDB OverviewDatabase candidates for HALDB Very large databases  Approaching 4GB limitation  Theoretical limit is now over 40 terabytes per database Medium and large databases  Parallel processing to meet time deadlines  Less frequent reorganizations due to more free space Any database  More frequent reorganizations  Making only parts of the data unavailable for database maintenance San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  21. 21. IBM Software Group | IMS Information Management Software IBM Software Group IMS Information Management Software VSAM to OSAMConversion Considerations San Ramon Users Group -Ramon User’s18 - Oct. 18 San October Group © Copyright IBM Corporation 2012 © Copyright IBM Corporation 2012
  22. 22. IBM Software Group | IMS Information Management Software VSAM to OSAM Conversion ConsiderationsPlanning:1. Buffer sizes – you are not limited to multiples of 4k.2. Pool definitions within the IMS control regions3. Sequential buffering for BMPs San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  23. 23. IBM Software Group | IMS Information Management Software VSAM to OSAM Conversion ConsiderationsConversion:1. IC the whole DB or HALDB2. Backup ACBLIB, DBDLIB, PSBLIB3. Run a GENJCL.RECOV for the HALDB with the JCLOUT DD pointing to a PDS to hold this JCL until needed (optional)4. Export the HALDB definitions using the PDU (optional but recommended) a. This is for fall back so you can use the ICs if required5. Unload database a. HALDB i. All partitions but can be concurrent unloads with one or more partitions per unload b. FF i. Single step unload San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  24. 24. IBM Software Group | IMS Information Management Software VSAM to OSAM Conversion ConsiderationsConversion (cont.):6. Change the DBD and run a DBDGEN7. Change partition information in the RECON a. CHANGE.PART …….DISABLE the current partitions i. You can use a DBRC GENJCL.USER command to accomplish this b. INIT.PART new partitions with the IMS DD using the update DBDLIB which is now OSAM c. If you ensure that the key ranges will not be altered during this process, you can delete the MASTER DB RECON record and INIT.DB and INIT.PART using the previous partition names. i. This will allow you to continue to use the same data set names ii. If the key ranges are not the same you run the risk of corrupting the ILKs and thus the self healing pointers would be broken San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  25. 25. IBM Software Group | IMS Information Management Software VSAM to OSAM Conversion ConsiderationsConversion (cont.):8. Create data sets definitions a. You can use a DBRC GENJCL.USER command to create the DEFINE CLUSTER/NON VSAM data set definitions for every partition in the HALDB9. Reload the database a. If you need to, run DFSUPNT0 to INIT the partitions b. Run the reload with the same concurrency used to unload them10. Run ACBGEN a. BUILD DBD=masterdb must be used11. IC the whole HALDB12. Remove old partitions a. If you used the DISABLE function, now you can DELETE.PART those old partitions San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  26. 26. IBM Software Group | IMS Information Management Software VSAM to OSAM Conversion ConsiderationsSystem changes:1. Modify buffer pools a. Modify DFSVSAMP member for all utilities/ DLI jobs b. Modify PROCLIB DFSVSMxx to allocate OSAM buffers c. Create subpools where required2. Modify PSBs for sequential buffering a. Add SB=COND to PROCOPT where required3. Modify CF Structures a. Create OSAM CF Structures b. Modify DFSVAMP member to name CF Structures i. CFNAMES,CFIRLM=DPRALOCK,CFVSAM=DPRAVSAM, CFOSAM=DPRAOSAM San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  27. 27. IBM Software Group | IMS Information Management Software Example of Allocating an OSAM Data Set //OSAMALLO JOB A,OSAMEXAMPLE//S1 EXEC PGM=IEFBR14//SYSPRINT DD SYSOUT=A//EXTENT1 DD VOL=SER=AAAAAA,SPACE=(CYL,(20,5)),UNIT=3390,// DSN=OSAM.SPACE,DISP=(,KEEP)//S2 EXEC PGM=IEFBR14//SYSPRINT DD SYSOUT=A//EXTENT2 DD VOL=SER=BBBBBB,SPACE=(CYL,(30,5)),UNIT=3390,// DSN=OSAM.SPACE,DISP=(,KEEP) . . .//LAST EXEC PGM=IEFBR14//SYSPRINT DD SYSOUT=A//EXTENTL DD VOL=SER=LLLLLL,SPACE=(CYL,(30,5)),UNIT=3390,// DSN=OSAM.SPACE,DISP=(,KEEP) San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  28. 28. IBM Software Group | IMS Information Management Software San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
  29. 29. IBM Software Group | IMS Information Management Software IBM Software Group IMS Information Management SoftwareOSAM – “The HealthyAlternative to VSAM”(720) 396-8545charles@us.ibm.comOctober 18, 2012 SourcesRedbooks:IMS Version 7 Performance Monitoring and Tuning Update – SG24-6404-00The Complete IMS HALDB Guide All You Need to Know to Manage HALDBs - SG24-6945-00“OSAM – the Healthy Alternative to VSAM” – Alan Cooper, Manchester, UK“VSAM to OSAM Conversion considerations” – Rick Long San Ramon User’s Group - Oct. 18 © Copyright IBM Corporation 2012
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