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VSAM created by JCL has a number of downsides especially if you're not using DATACLAS. Many values are defaulted, e.g. SHROPT, REUSE/NOREUSE, CISIZE, FREESPACE, SPEED/RECOVERY which could have undesired effects. You do have the option to automatically assign a DATACLAS to your datasets in the ACS routines so you don't have to code it in the JCL. That can be based on DSN or other variables.
With LIKE= Unless you explicitly code the SPACE parameter for the new data set, the system determines the space to be allocated for the new data set by adding up the space allocated in the first three extents of the model data set. Therefore, the space allocated for the new data set will generally not match the space that was specified for the model data set. Note that regardless of the units in which the model data set was allocated, the new data set will be allocated in tracks. This assumes that space was not specified on the JCL and is being picked up from the model data set
Read-only variables not available when LIKE is used. This can be quite crucial for dataset placement, so at least some of these values need to be included in the JCL along with LIKE to ensure they're available to ACS.
When you use the LIKE parameter on a JCL DD statement or the ALLOCATE command, the following read-only variable values are not available to the ACS routines:
&DSNTYPE
&DSORG
&MAXSIZE
&RECORG
&SIZE
Thus, a data set allocated like a second data set might go into in a different storage group than the second data set.