Merging and unmerging data sets

The dialog allows you to simplify your new configuration by merging some of the PDS and PDSE or HFS and zFS data sets in your order (see Merging UNIX file system data sets). You can merge target data sets to reduce the number of libraries with similar attributes and uses. For example, you can merge ISPF panel libraries to consolidate them. Later, when you save your configuration through the Save Configuration command (see Saving the configuration), the dialog also saves the data for each merged data set and its component data sets. The merged data sets are then available for merging with future ServerPac orders.

Unmerging a data set causes its attributes and space allocations to revert to their pre-merge values, with the exception of changes made to merged data sets through the CHANGE command (these are retained). Therefore, to avoid possible extra work, you should complete all merges and unmerges before going on to modify the attributes and space allocations of your merged data sets (as described in Modifying a data set's attributes).

While you can merge data sets from any data set list panel, you can use this function most effectively from the dialog's View and Change Facility (described in Viewing and changing data sets). Use the View and Change Facility to create lists of specific kinds of target data sets for merging, so that you spend less time excluding individual data sets from merges.

The merge and unmerge functionality is available for user-defined data sets as target-data sets.

When you select a data set for merging (through line command M), the Data Set Merge Candidates panel shown in Figure 1 is displayed.

Figure 1. Panel: Data set merge candidates

CPPP605M ------------- Modify System Layout ( MD053718 ) ---  ROW 1 TO 9 OF 9
COMMAND ==>                                                    SCROLL ==> PAGE
Data Set Merge Candidates for BFS.SBFSPLIB

Primary Commands:(? SET Locate Find Next Previous SORT Merge)
   Line Commands:(Information Select Conflict)

                                                
                                                Element    DS   MCAT IPL
S Data Set Name                                 Type      Type  Reqd Vol APF
- --------------------------------------------  -----    ----- ----- --- ----
  EOY.SEOYPENU                                  PNLENU    PDS   N     N   N
  GIM.SGIMPENU                                  PNLENU    PDS   N     N   N
  ICQ.ICQPLIB                                   PNLENU    PDS   N     N   N
  IOE.SIOEPNLE                                  PNLENU    PDS   N     N   N
  SYS1.DGTPLIB                                  PNLENU    PDS   N     N   N
  SYS1.SBPXPENU                                 PNLENU    PDS   N     N   N
  SYS1.SCBDPENU                                 PNLENU    PDS   N     N   N
  SYS1.SICEPENU                                 PNLENU    PDS   N     N   N
******************************* BOTTOM OF DATA ********************************

This panel shows the data sets from the display list that are eligible for merging with the selected data set (the target data set). Enter Information to the left of a candidate data set and press Enter to get information about data set attributes. Enter Select to the left of candidate data sets to select them for merging with the target data set.

In the Merge Candidates panel, observe the following conventions:

The Element Type column displays the element type of the data set, or one of these values:
- LMOD, for load libraries and PDSEs containing program objects
- DLIB, for distribution libraries.
For information about SMP/E element types, see SMP/E for z/OS Reference.
The DS Type column displays the data set type.
The MCAT Reqd column displays a Y if the data set must be cataloged in the master catalog.
The IPL Vol column displays a Y if the data set resides on the IPLVOL logical volume.
The APF column displays a Y if the data set requires APF authorization.

Not all data sets can be merged. The dialog restricts you from some, but not all, merge operations that would result in configurations that would be unworkable, lack important functions, or perhaps even be impossible to IPL. Specifically, the dialog prevents you from making the following types of merges:

Merging libraries that are required in the LPA with libraries that cannot reside in the LPA.
Merging libraries that are eligible to reside in the LPA with libraries that cannot reside in the LPA.
Merging libraries that are eligible to reside in the link list concatenation with libraries that cannot reside in the link list.
Merging data sets shipped with no secondary space with data sets with secondary space.

Also, the dialog prevents you from merging the following types of data sets:

The NUCLEUS data set
The SVCLIB data set
Operational data sets, such as PARMLIB and VTAMLST
SMP/E data sets
VSAM data sets

The dialog prevents you from merging any data sets that contain a member that matches (conflicts with) a member name within the selected data set. To see whether naming conflicts exist for a particular data set, enter line command C for the data set in the candidate list.

Lastly, you cannot merge a data set that is already a component of another merged data set. In this case, you must first unmerge the component data set from the merged data set before you can merge it with another data set.

The dialog allows you to merge data sets only when they share all of the following attributes with the target data set:

Record format (RECFM)
Logical record size (LRECL)
Data set type (DSNTYPE)
Eligibility to be managed by SMS
Compatible link list or LPA attributes
Origin library (DLIB or target library).

The candidate list automatically excludes any data sets that do not match these attributes of the target data set.

The candidate list excludes data sets with RECFM as U or V or VB, which have block size value higher than that of the target data set.

Also, the candidate list excludes data sets that do not match the SMS eligibility of the target data set. For a target data set that is managed by SMS, for example, the candidate list excludes data sets that are not eligible to be managed by SMS. Likewise, for a target data set that is not SMS-managed, the candidate list excludes data sets for which SMS management is required.

The candidate list can extend for several screens. You can scroll through the list and select data sets, as needed, for merging with the target data set.

When you are done selecting data sets, enter the M (merge) primary command on the command line of this panel and press Enter to merge the data sets. The dialog checks each selected component data set for member name conflicts with data sets that were previously merged into the target data set. If the dialog detects a conflict, a pop-up panel appears at the bottom of your screen. Press Enter to clear the pop-up and continue with the next selected data set in the candidates list. When the merge operation completes, the Data Set Merge Candidates panel displays a message indicating that the merge is successful.

Redisplaying the data set list panel now shows an asterisk in the X column for the target data set. Also, the component data sets that were merged into the target data set no longer appear in the list.