The shared DASD facility allows systems to share direct access storage devices. Systems can share common data and consolidate data when necessary. No change to existing records, data sets, or volumes is necessary to use the facility. However, the installation must write its applications to share DASD, and the reorganization of volumes might be desirable to achieve better performance.
Exercise careful planning in accessing shared data sets or shared data areas. Data integrity can not be assured without proper intersystem communication. For more information about how shared DASD relates to macros, see Macros used with shared DASD (RESERVE, EXTRACT, GETDSAB). Similarly, appropriate security procedures must be performed on each of the multiple systems involved in the sharing of DASD before data can be regarded as secure. Data sets that are intended to be protected via passwords or RACF® should be initially protected on each system before sensitive data is placed in them. This topic, as it refers to password protection, is discussed further under “System Configuration”.