The Move Volume utility performs DB2 SELECTs from the object directory tables (OSM_OBJ_DIR) to prepare the list of objects to be moved. Depending on the current status of the table, DB2 might do a table space scan or an index scan. With large DB2 tables, it is recommended that you verify that DB2 is to use index scans to enhance the efficiency and performance of the Move Volume utility.

The object selection is not overlapped with the read from optical or tape, write to optical or tape, or directory update processes. This means that the elapsed time to complete the MOVEVOL processing consists of the time to select the objects and the time to update the object directory tables after the object movement is complete.

Recommendation: Creating these additional DB2 indexes enhances the performance for the Move Volume utility; however, these indexes can negatively affect other OSMC process. After MOVEVOL processing has completed, drop these additional indexes and rebind the modified plans.

To improve performance for the Move Volume utility, perform the following steps:

1. Create an index on ODLSLOC and ODCLID for each storage group that contains a primary volume that is being processed. For first backup volumes, create an index on ODBKLOC and ODCLID for each storage group that has a significant number of objects (more than 10␠000). For second backup volumes, create an index on ODBK2LOC and ODCLID for each storage group that has a significant number of objects (more than 10␠000). Use the following SQL statements to define additional DB2 indexes.

      CREATE INDEX GROUPhlq.OBJDIRX4
             ON    GROUPhlq.OSM_OBJ_DIR                                           
             (
              ODLSLOC   ASC,
              ODCLID    ASC
             )
             USING      VCAT cat_name
             CLOSE      NO
             SUBPAGES   1 
            BUFFERPOOL BP1
            PCTFREE    10;
     CREATE INDEX GROUPhlq.OBJDIRX5                                              
            ON    GROUPhlq.OSM_OBJ_DIR                                           
            (              
             ODBKLOC   ASC,
             ODCLID    ASC 
            )              
            USING      VCAT cat_name
            CLOSE      NO           
            SUBPAGES   1            
            BUFFERPOOL BP1          
            PCTFREE    10;         
    

   Where: cat_name is the name of the catalog used under DB2. OAM does not create these indexes using the UNIQUE keyword.

   Because moving data from a backup volume requires access to all of the defined storage group directories, creation of the index on ODBKLOC (instead of ODLSLOC as in above example) is important for all storage groups that contain large numbers of objects (whether there are any backup objects on the volume being processed or not).

2. Execute RUNSTATS to collect data on the new indexes. See Tuning the DB2 databases for more information.

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3. Modify and run CBRPBIND to rebind the following DB2 plans to their packages for the affected storage group: CBRHSVOL, CBRHSBKV, CBRHSBCC, CBRHSPCC, CBRHORCL, and CBRHCNTL. See CBRPBIND, CBRHBIND and CBRHGRNT for information on binding these plans.

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4. Define data sets for the additional indexes. See CBRIALC0 for more information on defining these data sets.

   //STEPxx  EXEC PGM=IDCAMS
   //SYSPRINT DD SYSOUT=*
   //SYSDUMP  DD SYSOUT=*
   //SYSIN    DD *
    DELETE
    cat_name.DSNDBC.GROUPhlq.OBJDIRX4.I0001.A001
        CLUSTER
        PURGE
    DELETE
    cat_name.DSNDBC.GROUPhlq.OBJDIRX5.I0001.A001
        CLUSTER
        PURGE
    SET LASTCC=0
    SET MAXCC=0
    DEFINE CLUSTER
    (NAME(cat_name.DSNDBC.GROUPhlq.OBJDIRX4.I0001.A001)
             LINEAR
             SHAREOPTIONS(3 3)
             VOLUMES(vol_ser)
             CYLINDERS(pri_alloc sec_alloc)
             UNIQUE   )
           DATA
    (NAME(cat_name.DSNDBD.GROUPhlq.OBJDIRX4.I0001.A001))
    DEFINE CLUSTER
    (NAME(cat_name.DSNDBC.GROUPhlq.OBJDIRX5.I0001.A001))
            LINEAR
            SHAREOPTIONS(3 3)
            VOLUMES(vol_ser)
            CYLINDERS(pri_alloc sec_alloc)
            UNIQUE    )
          DATA
    (NAME(cat_name.DSNDBD.GROUPhlq.OBJDIRX5.I0001.A001))
   /*  

   Where: vol_ser is the volume serial the data set should be placed on; pri_alloc, sec_alloc is the number of primary and secondary allocations for the data set; cat_name is the name of the catalog used under DB2. These indexes are not created using the UNIQUE keyword.

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5. Run the Move Volume utility.

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6. Drop the DB2 indexes used during MOVEVOL processing.

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7. Execute RUNSTATS again.

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8. Rebind the following DB2 plans: CBRHSVOL, CBRHSBKV, CBRHSBCC, CBRHSPCC, CBRHORCL, and CBRHCNTL.

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See CBRISQL0 for sample job control language (JCL).