Using CHANGE.RECON to reorganize a RECON data set

You can reorganize a RECON data set online if you are using dynamic allocation for the RECON data set by using the CHANGE.RECON command. A spare RECON data set must be available.

In this situation, you can issue the CHANGE.RECON command with the REPLACE option. This causes DBRC to copy and reorganize the active RECON data set (specified on the CHANGE command) to the spare data set. VSAM removes all CI and CA splits, and restores the original FREESPACE attributes.

The CHANGE command also deallocates the old RECON data set (the one that needed reorganization). Before you can delete and redefine this data set, however, you must wait for all other subsystems that are using it to deallocate it. If you redefine the data set with the same name it originally had, it is available to the online system for use as a spare data set. You can repeat this process to reorganize the second active RECON data set. If you use JCL in order to allocate data sets, dynamic deallocation does not occur.

If you do not use dynamic allocation or if a spare RECON data set is not available, you must wait for the online subsystem and all other subsystems that access the RECON data set to deallocate it before you can reorganize.