Use the REPRO command to create a duplicate data set for back up. For information about using REPRO, see Copying and Merging Data Sets.

If you are accessing a data set using RLS, see Using VSAM Record-Level Sharing.

REPRO provides you with several options for creating backup copies and using them for data set recovery. The following are suggested ways to use REPRO:

1. Use REPRO to copy the data set to a data set with a different name.

   Either change your references to the original copy or delete the original and rename the copy.

2. Create a backup copy on another catalog, then use the backup copy to replace the original.
   • Define a data set on another catalog, and use REPRO to copy the original data set into the new data set you have defined.
   • You can leave the backup copy in the catalog it was copied to when you want to replace the original with the backup copy. Then, change the JCL statements to reflect the name of the catalog that contains the backup copy.
3. Create a copy of a nonreusable VSAM data set on the same catalog, then delete the original data set, define a new data set, and load the backup copy into the newly defined data set.
   • To create a backup copy, define a data set, and use REPRO to copy the original data set into the newly defined data set. If you define the backup data set on the same catalog as the original data set or if the data set is SMS managed, the backup data set must have a different name.
   • To recover the data set, use the DELETE command to delete the original data set if it still exists. Next, redefine the data set using the DEFINE command, then restore it with the backup copy using the REPRO command.
4. Create a copy of a reusable VSAM data set, then load the backup copy into the original data set. When using REPRO, the REUSE attribute permits repeated backups to the same VSAM reusable target data set.
   • To create a backup copy, define a data set, and use REPRO to copy the original reusable data set into the newly defined data set.
   • To recover the data set, load the backup copy into the original reusable data set.
5. Create a backup copy of a data set, then merge the backup copy with the damaged data set. When using REPRO, the REPLACE parameter lets you merge a backup copy into the damaged data set. You cannot use the REPLACE parameter with entry-sequenced data sets, because records are always added to the end of an entry-sequenced data set.
   • To create a backup copy, define a data set, and use REPRO to copy the original data set into the newly defined data set.
   • To recover the data set, use the REPRO command with the REPLACE parameter to merge the backup copy with the destroyed data set. With a key-sequenced data set, each source record whose key matches a target record's key replaces the target record. Otherwise, the source record is inserted into its appropriate place in the target cluster. With a fixed-length or variable-length RRDS, each source record, whose relative record number identifies a data record in the target data set, replaces the target record. Otherwise, the source record is inserted into the empty slot its relative record number identifies. When only part of a data set is damaged, you can replace only the records in the damaged part of the data set. The REPRO command lets you specify a location to begin copying and a location to end copying.
6. If the index of a key-sequenced data set or variable-length RRDS becomes damaged, follow this procedure to rebuild the index and recover the data set. This does not apply to a compressed key-sequenced data set. It is not possible to REPRO just the data component of a compressed key-sequenced data set.
   • Use REPRO to copy the data component only. Sort the data.
   • Use REPRO with the REPLACE parameter to copy the cluster and rebuild the index.