z/OS DFSMS allows access to data set attributes for migrated SMS-managed data sets, without having to recall the data set if the data set was migrated under DFSMS/MVS V1R3 or later. Supported data set types are SMS-managed PS, VSAM ESDS, VSAM KSDS, VSAM RRDS, PDS, and PDSE. Migrated PDS/PDSE members are not supported.

The z/OS NFS server is able to obtain the attributes of a supported SMS-managed migrated data set without recalling the data set. Attributes such as the time stamp and file size are saved to DASD. Subsequent file size requests do not cause a recall of the supported SMS-managed migrated data set, thus improving performance. However, when the data set is modified outside the server by a non-NFS application (for example, by the TSO/E editor) before it was migrated, the stored file size could be incorrect. When the data set is accessed again by the server, a recall must be done to determine the correct file size.

When a request is made to remove any of the supported SMS-managed migrated data sets, the data set will be deleted without recall. For PDS and PDSE migrated data sets, the data set will be recalled in order to read its member information.