Database buffer specifications and option parameters
You define the VSAM and OSAM database buffer pool specifications and IMS performance and trace options in the DFSVSMxx member of the IMS.PROCLIB data set, which is pointed to by the PROCLIB DD statement of the DBCTL startup procedure (DBC).
The last two characters of the DFSVSMxx member are a suffix. You specify this suffix in the VSPEC parameter of the DBCTL startup procedure. See System definition in IMS product documentation for guidance on the syntax of these parameters and Database administration in IMS product documentation for guidance on specifying the database buffer pool parameters. For an illustration of the parameters involved in DBCTL startup, see Illustration of DBCTL startup parameter creation and selection.