The serialization mechanism used during a logical dump of a mounted HFS data sets consists primarily of the SYSZDSN enqueue macro and the BPX1QSE quiesce macro. A shared SYSZDSN enqueue provides serialization if a data set that you want to dump is not mounted for update. To mount an HFS data set for update, z/OS® UNIX System Services (z/OS UNIX) must obtain an exclusive enqueue on the SYSZDSN. The shared enqueue on the SYSZDSN prevents z/OS UNIX from mounting the data set for update during the dump.

If you mount an HFS data set for update before you dump it, DFSMSdss issues the BPX1QSE macro to prevent updates to the data set for the duration of the dump. For non-shared file systems, you must run the DFSMSdss dump job on the same system where the data set is mounted for update. For shared file systems, you can run the DFSMSdss dump job from any system in the sysplex.

DFSMSdss can honor the DELETE keyword for an HFS data set during logical dump only if the data set is unmounted. For delete processing, the data set must be enqueued exclusively.