You can define data classes specifically for data sets eligible for VSAM RLS. When you have data classes with VSAM RLS parameters, you do not need to change current AMS DEFINE statements and job streams.
Recommendation: To avoid having too many data classes, you should specify the JCL LGSTREAM ID keyword for SMS VSAM data sets defined by JCL instead of the Logstream ID attribute in the data class. See Defining data class attributes for more information.