Adding multiple disk pack volumes to Datacom files without SMS

Products

• Datacom/DB
• Datacom
• Datacom/AD

Issue/Introduction

We are trying to reallocate Datacom database files on a system that doesn’t have SMS storage.
We would like to add additional multiple disk pack volumes to database file areas to be used by dynamic extend.

Environment

Release : 15.1

Resolution

For non-SMS datasets, to make more volumes available for dynamic extends there is no need to reallocate the files.

More volumes can be added by uncataloging the data set and re-cataloging it with additional volumes which will then be available for use by dynamic extends.

Perform the following procedure:

1. Close the DBID in CICS using command:
   DBOC CLOSE=nnn

2. Run DBUTLTY with the following 2 commands to close the dbid in Datacom:
   ACCESS STATUS=OFF,DBID=nnn,USERS=FAIL  
COMM OPTION=CLOSE,DBID=nnn              
   
   If the ACCESS command fails, it will tell you what job has the DBID open. Terminate he job and run the ACCESS again.

3. Note the volumes the dataset currently resides in and the order of the volumes. You can get the information in a few ways:
   
   
   • Run a full CXX report and look at the dataset for the area. Datacom extracts the volser information from the catalog when the dbid is opened.
     
     
   • In ISPF option 3.4 by selecting the dataset with option I, putting the cursor on the + sign next to the first volume and pressing enter.
     
     
   • Use the IDCAMS LISTCAT  command:
     LISTC ENT('dataset_name') VOL  
     
     
4. Uncatalog the data set:
   
   //*
//* UNCATALOG DATASET
//*
//UNCAT    EXEC PGM=IEFBR14                             
//SYSUT2   DD DSN=database.file,DISP=(OLD,UNCATLG)   
   
   
5. Re-catalog the dataset with the original volumes in the order they were originally allocated plus the additional new volumes to the right of the list.
   It is important not to miss any volumes or specify volumes in the wrong order when re-cataloging the file otherwise the data will be corrupted and must then be restored from a backup and a forward recovery run.
   
   //*
//* RECATALOG WITH ADDITONAL VOLUMES
//*
//RECAT    EXEC PGM=IEFBR14                             
//SYSUT2   DD DSN=database.file,
//            VOL=SER=(oldvolser1,oldvolser2,oldvolser3,newvolser1,newvolser2),
//            DISP=(OLD,CATLG),UNIT=3390                

6. Verify the volumes are correct by checking in ISPF option 3.4 or using the IDCAMS LISTCAT  command.

7. You can now run a DBUTLTY EXTEND to verify the new volume is used.
   
   
8. Re-enable MUF access by running DBUTLTY with: 
   ACCESS STATUS=WRITE,DBID=nnn 
   
   
9. Future dynamic extends will use the additional volumes.

After adding more volumes, if a DBUTLTY INIT is run it will default to allocating extents across all volumes. You can control this by adding the VOLUMES parameter to the INIT.
To INIT the file and only use the first volume: 
INIT AREA=aaa,DBID=nnn,VOLUMES=1

Additional Information

See the Datacom documentation sections Creating and Maintaining Data Areas, EXTEND, Multivolume INITs in INIT Data Area and INIT IXX.

For SMS managed files see article 33629 - Adding volumes to SMS-managed database files in Datacom.

An alternative to adding additional volumes is to allocate a larger file and perform an Online Area Move (OAM), see article Using the Online Area Move (OAM) process.