To enable CA reclaim for the majority of data sets, and disable it for just a few data sets, you could perform the following:

1. Disable CA reclaim for the appropriate data sets by using the ALTER command with NORECLAIMCA or by defining data sets with a data class for which the CA reclaim attribute causes CA reclaim to be disabled.
2. Enable CA reclaim for the system either by issuing the SETSMS command or by modifying PARMLIB member IGDSMSxx and then performing an IPL.