Converting an SMS-managed, non-striped data set to a striped data set

Convert SMS-managed, non-striped data sets to SMS-managed, striped data sets before you execute jobs that might abend with Sx37 abends because they exceed the maximum number of volumes (59).

If an Sx37 abend occurs for an SMS-managed, non-striped data set due to the number of volumes for the data set exceeding 59 volumes, the data set cannot be recovered and an XRST cannot be completed.

The recovery cannot be completed because the SMS-managed, non-striped data set must be copied to an SMS-managed, striped data set with a larger primary and secondary allocation space parameter. When copying SMS-managed data sets, the copy process uses all the new space that is defined, starting with the first volume, which results in the checkpointed data record being moved not only to a different volume, but also having a different relative track and record (TTRZ, or TTTRZ for large format data sets). The copy process thus invalidates the restart position saved in the X'18' log record.

Migration from GSAM/BSAM non-striped data sets, which use TTRZ (or TTTRZ for large format data sets) for repositioning, to striped data sets, which use relative block number (RBN), results in an XRST failure or possibly an XRST reposition on the wrong data record. You cannot process a GSAM/BSAM non-striped data set, have an error condition occur, copy the data set to a striped data set, and then attempt to perform an XRST command. You must convert GSAM/BSAM non-striped data sets to striped data sets when you learn that your GSAM/BSAM databases are SMS-managed data sets and there is any chance that a job accessing that database might abend with an Sx37 number of volumes exceeded condition and that an XRST command is required.

To convert to an SMS-managed, non-striped data set to a striped data set:

Procedure

  1. Copy the non-striped data set to a new striped data set and use the same block size and device type.
  2. Specify the RECFM=U record format for both the input and the output data set to avoid any reblocking.
  3. When using DFSMS striped data sets, the restriction regarding maintaining the same number of records on the copied from and copied to volumes does not apply because with striped data sets, GSAM uses the RBN for NOTE/POINT, not the TTRZ (or TTTRZ for large format data sets).

In addition, GSAM supports DFSMS striped (extended format) data sets for both VSAM and BSAM.