After the introduction of data sharing in DB2 it has become rather difficult to keep track of which DB2 subsystems that are data sharing group members and which MVS systems they are running on. Fortunately there exist a DB2 command that gives you all this information. It is called -DIS GROUP.

An easy way of executing a -DIS GROUP command is by using the following REXX. The REXX is executed using command TSO %DB2GROUP <SSID> if you choose to call the REXX DB2GROUP:

/* REXX: DB2GROUP */
ARG SSID
PUSH "END"
PUSH "-DIS GROUP"
ADDRESS TSO "DSN SYSTEM("SSID")"

Here is an example of the produced output from command TSO %DB2GROUP DB1A:

DSN7100I -DB1A DSN7GCMD
*** BEGIN DISPLAY OF GROUP(DSNDB10 ) GROUP LEVEL(610)
                                     GROUP ATTACH NAME(DB10)
--------------------------------------------------------------------
DB2                                    DB2 SYSTEM    IRLM
MEMBER   ID  SUBSYS CMDPREF   STATUS   LVL NAME      SUBSYS IRLMPROC
-------- --- ----   --------  -------- --- --------  ----   --------
DB1A       1 DB1A   -DB1A     ACTIVE   610 MVSA      DJ1A   DB1AIRLM
DB1B       2 DB1B   -DB1B     ACTIVE   610 MVSB      DJ1B   DB1BIRLM
DB1C       3 DB1C   -DB1C     ACTIVE   610 MVSC      DJ1C   DB1CIRLM
--------------------------------------------------------------------
SCA   STRUCTURE SIZE:     1024 KB, STATUS= AC,   SCA IN USE:    11 %
LOCK1 STRUCTURE SIZE:     1536 KB
NUMBER  LOCK ENTRIES:      262144
NUMBER  LIST ENTRIES:        7353, LIST ENTRIES IN USE:           0
*** END DISPLAY OF GROUP(DSNDB10 )
DSN9022I -DB1A DSN7GCMD 'DISPLAY GROUP ' NORMAL COMPLETION

This output is copied directly from a DB2 manual and is a hipothetical example. I have removed a couple of subsystems from the list, though. First important information from the output is GROUP ATTACH NAME. This name is the common name which you can use on all the listed MVS systems (column SYSTEM NAME). A TSO %DB2GROUP DB10 will produce almost the same result as in the listed example. The next important information is column SUBSYS which lists the names of all the DB2 subsystems that are part of the DB2 data sharing group. The last important information is listed in column SYSTEM NAME which contains the name of the MVS system where the DB2 subsystem is executing. I can now conclude that the -DIS GROUP command was issued on MVSA because the DB2 subsystem DB1A is running on this MVS.

If you want to know what the other columns contain and what the lines at the bottom of the output means you can read all about it in the DB2 Manual Command reference.