A pubset is declared a potential shared pubset with the SET-PUBSET-ATTRIBUTES command. This command is also used to predefine the master processor of the pubset and the attributes for a master change. The following setting is recommended:
/SET-PUBSET-ATTRIBUTES PUBSET=<catid>, - / SHARED=*YES, - / MASTER=<sysid1>, - / BACKUP-MASTER=<sysid2>, - / ALTERNATE-BACKUP=*BY-SHARER
If MASTER-CATALOG-ENTRY (see section “Entering the shared pubsets in the MRSCAT”) contains SHARED-PUBSET=*YES the following applies to the next pubset session:
When the IMPORT-PUBSET command is used without specification of the SHARER-TYPE operand on the processor with <sysid1>, this starts a master import, i.e. the shared pubset session begins and the processor with <sysid1> becomes the master processor of the shared pubset (<catid>). During a master change (see "Failure of a processor in a shared pubset network"), one of the two processors with <sysid2> and <sysid1> is a backup master while the other is the master, and vice versa. If a master change is necessary at a time when the current backup master is not active, a third processor that is currently an active slave, is implicitly named the backup master and the master change is initiated.
The SET-PUBSET-ATTRIBUTES command causes entries to be made in the SVL of the pubres of a pubset. The specification SHARED=*YES identifies a pubset (in its SVL) as a potential shared pubset. Whether a pubset that is thus identified is actually used as a shared pubset is decided when the pubset is imported and depends on whether local multiple usability is entered in the MRSCAT, or if the pubset is entered as multiply usable in the MRSCAT, by the specifications in the IMPORT-PUBSET command, USE and SHARER-TYPE operands.