Data sets that MERGECOPY uses
The MERGECOPY utility uses a number of data sets during its operation.
The following table lists the data sets that MERGECOPY uses. The table lists the DD name that is used to identify the data set, a description of the data set, and an indication of whether it is required. Include statements in your JCL for each required data set and any optional data sets that you want to use.
| Data set | Description | Required? |
|---|---|---|
| SYSIN | Input data set that contains the utility control statement. | Yes |
| SYSPRINT | Output data set for messages. | Yes |
| Image copy data set | Image copy data set that contains the resulting image copy. Specify its DD name with the COPYDDN option of the utility control statement. The default DD name is SYSCOPY. | Yes |
| Work data set | A temporary data set that is used for intermediate merged output. Specify its DD name with the WORKDDN option of the utility control statement. The default DD name is SYSUT1. | Yes |
| Input data sets | Image copy data sets that you can preallocate. You define the DD names. | No |
- Table space
- Object whose copies are to be merged.
The following object is named in the utility control statement and does not require a DD statement in the JCL:
Data sets
The input data sets for the merge operation are dynamically allocated. To merge incremental copies, allocate in the JCL a work data set (WORKDDN) and up to two new copy data sets (COPYDDN) for the utility job. You can allocate the data sets to tape or disk. If you allocate them to tape, you need an additional tape drive for each data set.
With the COPYDDN
option of MERGECOPY, you can specify the DD names for the output data
sets. The option has the format COPYDDN (ddname1,ddname2),
where ddname1 is the DD name for the primary
output data set in the system that currently runs Db2, and ddname2 is
the DD name for the backup output data set in the system that currently
runs Db2. The default for ddname1 is
SYSCOPY.
The RECOVERYDDN option of MERGECOPY lets you specify
the output image copy data sets at the recovery site. The option has
the format RECOVERYDDN (ddname3, ddname4),
where ddname3 is the DD name for the
primary output image copy data set at the recovery site, and ddname4 is
the DD name for the backup output data set at the recovery site.
Defining the work data set
The work data set should be at least equal in size to the largest input image copy data set that is being merged. Use the same DCB attributes that are used for the image copy data sets.