If the caller needs to prevent DADSM functions from being performed against the set of volumes in the copy pool during the backup, it is the caller's responsibility to do so. This should be done by serializing on all of the VTOCs before invoking DFSMShsm. Serializing on the VTOC prevents DADSM functions and also prevents DFSMSdss functions such as DEFRAG, COPY and RESTORE from modifying the VTOCs. When you perform this serialization, use the NOVTOCENQ parameter with the FRBACKUP command to indicate that DFSMSdss should not serialize on the VTOC of each volume.