How to allocate larger OPS/LOG and define dynamically to the region?
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How to allocate larger OPS/LOG and define dynamically to the region?


Article ID: 221143


Updated On:


OPS/MVS Event Management & Automation


We want to use a new large dataset for OPSLOG. What will be the procedure for this (without recycling OPSMVS if possible)?

Can you please provide the JCL to allocate the dataset?

What can be maximum value of BROWSEMAX in OPSMVS v14.0? And what value do you recommend?


Release : 13.0 13.5 14.0

Component : OPS/MVS


1. Allocate the OPSLOG dataset

Create JCL as follows, replace <Jobcard>                       with the appropriate jobcard
                                                  <OPSLOG_dsn>             with the new OPSLOG dataset name
                                                  <OPSLOG_cylinders>    with the number of cylinders to allocate
                                                  <OPSLOG_volser>         with the desired volser   

//STEP01   EXEC PGM=IDCAMS                                           
//SYSPRINT DD SYSOUT=*                                               
//SYSIN    DD *                                                      
 DEFINE CLUSTER ( NAME(<OPSLOG_dsn>)                        -             
                  CYLINDERS(<OPSLOG_cylinders> 0)           -
                  VOL(<OPSLOG_volser>)                      -             
                  SHAREOPTIONS(2 3)                         -                
                  LINEAR )                                  -                      
        DATA ( NAME(<OPSLOG_dsn>.DATA') )

The OPSLOG dataset name chosen must be unique to the LPAR and the region using it. 

Be sure to include the “0” secondary allocation in the CYLINDERS definition above when replacing <OPSLOG_cylinders> with the number of cylinders you wish to use for the primary allocation.

Use the following chart to select the number of primary cylinders to be used based upon the region's current message rate:

DASD Requirements for the OPSLOG

[Note- the requirements can be found in the Storage Requirements section of the manual for the release that is being used]

BROWSEMAX sets the number of messages recorded in OPSLOG before it wraps, and the maximum allowable value is 2950000. Accordingly, in the chart above, the maximum size allowable for OPSLOG is 3553 cylinders for a 3380 DASD storage unit and 2960 cylinders for a 3390 unit to allow for a maximum of 2950000 messages contained in OPSLOG.

There is not a “recommended” value for BROWSEMAX because it should be set according to the current region message rate and the desired number of messages to be kept in OPSLOG.

Once the JCL above has been modified as indicated, submit it to allocate the new OPSLOG dataset. 


2. Define the new OPSLOG to OPS/MVS

An OPSLOG dataset name of CAOPSMVS.OPS140.XE38.OPSLGTST will be used in this example.

Once the new OPSLOG is allocated it must be defined to OPS/MVS. This is done in he initial REXX exec OPSSPAxx in the hlq.CCLXCNTL library using these keywords (in this example, a low level qualifier of OPLGTST was used to differentiate the dataset name from the name currently in use):

primary_OPSLOG_dsn       = 'CAOPSMVS.OPS140.XE38.OPLGTST'
primary_OPSLOG_browsemax = '400000'  

Locate the above lines in the OPSSPAxx member and change the values in RED according to the new OPSLOG dataset name and the desired value for BROWSEMAX. These values will be picked up the next time OPS/MVS is started.


3. Dynamically define the new OPSLOG to the running OPS/MVS region

In OPS/MVS from the primary menu, select option 4.13, which results in the following panel:


On the command line, enter "new":


On the screen that follows, choose the new log name to be displayed, the OPSLOG dataset name and the desired value for BROWSEMAX to match that specified in the OPSSPAxx member:


Press ENTER to validate the data, then PF3 to apply. Now the new log can be seen in the list as “defined” but not active:


Enter “A” next to the new log to activate it, and then press ENTER:


An opportunity to modify settings is presented. If everything is satisfactory, press ENTER again to confirm the operation:


Verify the action by pressing ENTER again:


The new OPSLOG may show “Pending Active” status until ENTER is pressed a time or two to refresh the screen, after which it should become active. Enter “L” next to the new log to make it the LIVE log:


Confirm the action on the next screen by pressing ENTER again, and the new log should now become the LIVE log:


The new OPSLOG is now recording log data, and the changes made in the OPSSPAxx REXX member will ensure continued use of the new log upon subsequent restarts.                                

Additional Information

OPSLOG Initialization