Why am I getting the message DFS3488?

Document ID : KB000014290
Last Modified Date : 14/02/2018
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Introduction:

Running File Master Plus for IMS, as a BMP.    

Question:

Is there a better way to set up the BMP environment for the FMP for IMS, other than as follows?

 

IMS has the following Dynamic allocation for ACBLIB 

 

DFSMDA TYPE=IMSACBA 

DFSMDA TYPE=DATASET,DSNAME=IMST.ACBLIBA 

DFSMDA TYPE=DATASET,DSNAME=IMST.IXP.ACBLIB 

DFSMDA TYPE=IMSACBB 

DFSMDA TYPE=DATASET,DSNAME=IMST.ACBLIBB 

DFSMDA TYPE=DATASET,DSNAME=IMST.IXP.ACBLIB 

 

File Master for IMS has the following for the BMP environment 

 

ACBLIB #1 ===> 'IMST.ACBLIBF' 

#2 ===> __________________ 

#3 ===> __________________ 

DOPT ACBLIB ===> 'IMST.IXP.ACBLIB' 

DBDLIB #1 ===> 'IMST.DBDLIB' 

 

We have a automatic process that perform an IMS online change (/MODIFY PREPARE + /MODIIFY COMMIT) every 15 minutes along the day. In rare occasions, we faced the message 

DFS3488 ERROR DURING ENQUEUE FOR DDNAME IMSACBx 

What we have realized by researching the log is this message DFS3488 when occurs, always there is someone using the File Master in the BMP environment listed above. 

What we think is IMST.IXP.ACBLIB is causing the contention. FMP for IMS allocates the IMST.IXP.ACBLIB to build the dynamic ACB while IMS is trying to perform the online change for ACBLIB. 

 

Environment:
Set up File Master Plus for IMS, in a BMP environment
Answer:

Unfortunately no. This is implied by the need to indicate in the DOPT ACB field the name of a library that is in the IMSACB concatenation.

If the DFSMDA definitions reflect the IMSACBx allocations in your control region you don't have much of a choice because IMS takes an EXCL enqueue against the data sets that come first in the IMSACBx concatenations and FMIMS would not be able to store the dynamic ACBs in these libraries. 

DOPT libraries are not mandatory in an IMS region but in that case IMS would not be able to process dynamically generated ACBs 

A common practice is to keep separate the dynamically generated ACBs by third party vendors from in-house stuff. If you had several providers or several products that generate ACBs they could use the same dynamic library. In some installations there's one DOPT Library per vendor. At this point it is more a matter of policy than effciency. 

 

Additional Information:

It is correct, that the FMIMS product creates its dynamic ACBs in the Library referred to as the DOPT ACBLIB in the FMIMS environment. 

As indicated by the DFS3488 message it is likely the Library was not available for the MODIFY command because of an on-going ACB build.  

I don't see any way to avoid this situation since the DOPT Library must be one of the libraries allocated in the IMSACBx statements to the exception of the first one which is only available to IMS.