If you issue a checkpoint or if a restart occurs, none of the VSAM data sets open in your region at that time can be using CBUF processing. If you issue checkpoints, you should open the VSAM data sets that are eligible for CBUF processing with a disposition of OLD, or CLOSE them before the checkpoint. Note that, if an alternate index was using CBUF processing, the associated base cluster and any other paths open over that base cluster must also be closed before the checkpoint, even if they are not using CBUF processing.