Changing DSNTYPE on Datacom areas from BASIC to LARGE
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Changing DSNTYPE on Datacom areas from BASIC to LARGE


Article ID: 236309


Updated On:


Datacom Datacom/DB Datacom/AD


The majority of our areas are currently defined as DSNTYPE=BASIC. Our systems programmer wants to see them converted to DSNTYPE=LARGE. 
Is there any Datacom function or utility that will allow to do this instantly?


Release : 15.1



DSNTYPE is an attribute of a file when it is allocated. Therefore, there is no Datacom function or utility that can change this once the file has been. A new allocation with DSNTYPE=LARGE would be done regardless of whichever method is chosen below. 

Method 1:  Online Area Move (OAM) function would be the recommended approach as you can define the new file with the size and other attributes you want, and then let the MUF handle the move over to the new file and the rename of the file when it is done all without having to go offline. Also check out How to prepare and index and data area for OAM as this doc has been updated to include graphics of the logic flow of OAM. 

Method 2: If you elect not to use OAM, you can still perform the traditional method if you have some down time to run a backup, allocate, and load of the new file.

Additional Information

Review OAM limitations and best practices

Other benefits that OAM provides are to change:

  • a Datacom area from NON-SMS to SMS
  • a Datacom area from single to multi-volume