1. A computer program product for modifying a virtual storage access method (VSAM) data set during open time, the computer program product comprising a computer readable storage medium having computer readable program code embodied therewith, wherein the computer readable storage medium in not a transitory signal, the embodied program code readable/executable by a processor to: open, by the processor, a VSAM data set; and modify, by the processor, a VSAM control block structure for the VSAM data set while the VSAM data set is open during an open time in which static data set characteristics and/or job parameters have been defined for the VSAM data set by interacting with the VSAM data set within a VSAM dynamic address space using at least one interface selected from a group consisting of: a VSAM console interface and a VSAM programming interface, the interacting comprising performing at least one function selected from a group consisting of: changing, by the processor, one or more parameters of at least one associated job; changing, by the processor, at least one VSAM data set characteristic; and dynamically enabling, by the processor, at least one VSAM record management trace in any address space.