Using DCOLLECT data

DCOLLECT is an IBM utility that queries all online DASD and produces a file containing several record types.

By default, DCOLLECT produces the following types of records:

  • VOLUME (V)
    V-type records contain information about used and free space for each volume.
  • Data Set (D)
    D-type records contain information about used and free space for each data set.
  • VSAM (A)
    A-type records contain information about VSAM data sets.

You can use two options to obtain DCOLLECT records:

  • You can include the DCOLLECT step in the UIE job. In this case, DCOLLECT results are written to a temporary file and passed to the next UIE step. After the end of the UIE job, the temporary file is deleted.
  • You can run DCOLLECT separately, save its result in a permanent data set, and provide this data set to UIE as input. We recommend that you run DCOLLECT on the system on which all DASD are accessible. It is possible to run DCOLLECT on several systems and concatenate the output files in the DCOL input DDname for the UIE job.

If you are processing only V-type records, you can have several sets of DCOLLECT data in the same file. UIE sorts the V-type records and uses only the latest V-type record for each device. However, we do not recommend putting several sets of DCOLLECT data in the same file to avoid processing time.

However, if you are processing both D-type and V-type records, you cannot have several sets of records for the same devices in the DCOLLECT file. Because of the high volume, D-type records are not sorted before the processing and are not stored individually. A DCOLLECT file for a medium size DASD farm can easily exceed the size of a 3390-3. As a result, D-type records are processed on the fly. If several sets of records are present for the same volume, the size of data sets will be double-counted.

When processing V-type records, UIE collects information on the free and allocated spaces for each physical volume. If the DCOLLECT file contains several records for some devices, UIE uses the latest record. The information that is obtained is applied to all intervals in the current UIE run.

When processing A-type and D-type records, UIE aggregates space information from individual D-type records (allocated space, used space, and so on) and A-type records (used space) into Data Set Groups. The creation of Data Set Groups is controlled by the following commands:

  • DSGROUPCONTROL
  • DSGROUP

Note

You can use the DSGROUP command to create data set groups based on data set name, data set qualifiers, storage group, storage class, data class, and management class names. The D- type record contains all of these fields. The A- type record contains only the data set name. If you want to process the A-type records to obtain VSAM information, your DSGROUP commands can only use the data set name or data set qualifier parameters. If your DSGROUP commands use the storage group, storage class, data class or management class name parameters, UIE will skip the A-type records.

For more information about these commands, see DSGROUP and DSGROUPCONTROL.

The DCOLLECT file with D-type and A-type records can be very large, even multivolume. When D and A type records are present in the DCOLLECT file, UIE processes them by default and generates additional data in the Visualizer file. D-type and A-type record data is not used in the XML model. If you want to disable D-type and A-type record processing, you can use the BYPASSREC DCDS command. For more information, see BYPASSREC.

If you want to disable the D-type and A-type record collection in the IDCAMS step, use the NODATAINFO  command in the DCOLLECT step JCL as follows:

//S1  EXEC PGM=IDCAMS
//SYSPRINT DD SYSOUT=*
//OUTDS    DD DSN=RDBxxx.DCOLLOUT.VOLxxx,   ......
   DCOL -
     OFILE(OUTDS) -
     NODATAINFO -
     ERRORLIMIT(200)
/*

Related topic

Processing-performance-data

 

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