Large format data sets are a type of physical sequential data set, other than extended format data sets, which can grow beyond a size limit of 65␠535 tracks on each volume. That size limit applies to z/OS conventional (basic format) sequential data sets. Large format data sets can exploit the increased storage capacity of most hardware storage devices, and reduce the need for very large data sets to span multiple volumes.

To create a large format data set with z/OS NFS, specify a data class which has a dsntype value of large. The dsorg value must be ps, psu, or omitted.

For more information about large format data sets, see z/OS DFSMS Using Data Sets.