The size of SYSEAM files must always be less than 32 GB.
The size of SYSEAM files is determined by specifications in the MRSCAT entry.
It is defined with the ADD-MASTER-CATALOG-ENTRY EAM=*PAR(...) command when the MRSCAT entry is created, and can be changed for an existing entry with the MODIFY-MASTER-CATALOG-ENTRY EAM=*PAR(...) command.
If no EAM specifications exist in an MRSCAT entry, the corresponding system parameters apply. Thus the maximum size specification possible (64512 units) guarantees that a SYSEAM file always remains smaller than 32 GB.
Furthermore, if a primary or secondary allocation is necessary, the appropriate parameterization within EAM ensures that a SYSEAM file cannot become larger than
32 GB.
The only way that a SYSEAM file can exceed the 32-GB limit is if it is explicitly created by systems support using FILE or CREATE-FILE and the corresponding file size.
The first EAM access to this file will however be rejected, and the message DMS0854
will be output to the console.
DMS0854 FILE SIZE OF SYSEAM FILE (&00) MAY NOT EXCEED 32 GIGABYTES
The action associated with this message is to delete the corresponding SYSEAM file and to have systems support create the file again with a file size that is not critical.