IDCAMS IMPORT

The IDCAMS IMPORT command restores a VSAM cluster, alternate index (AIX), or catalog from a backup that was created with the IDCAMS EXPORT command. The backup is stored as a sequential dataset; IMPORT reads that dataset and recreates the VSAM object, including catalog information and data. You can restore to the same name or to a new name (NEWNAME or OUTDATASET), and you can specify volumes for the restored object. IMPORT is the counterpart to EXPORT: use EXPORT to create a portable backup, and IMPORT to restore it on the same system or on another system. This page explains the IMPORT syntax, when to use IMPORT instead of REPRO, the main parameters (INFILE, INDATASET, OUTDATASET, NEWNAME, INTOEMPTY, VOLUMES), and how to restore after a failure or for testing.

What IMPORT Does

When you run EXPORT, IDCAMS writes the VSAM object (cluster, AIX, or catalog) to a sequential dataset in a format that includes both the data and catalog-related information. That format is not plain record copy; it is a backup format that preserves structure and attributes. IMPORT reads that sequential dataset and recreates the VSAM object. The target can be a new name (you are restoring to a different cluster name) or the same name (you are restoring over a lost or damaged cluster). In many implementations, IMPORT can create the target cluster as part of the restore, so you do not have to DEFINE CLUSTER first. That differs from REPRO, which copies records from a source to an already-defined target. So IMPORT is for "restore from EXPORT backup"; REPRO is for "copy from one dataset to another."

When to Use IMPORT

Use IMPORT when you have a backup that was created with EXPORT and you need to restore the VSAM object. Typical situations: (1) Recovery after a failure—the cluster was damaged or lost and you have an EXPORT backup. (2) Restoring to a test or parallel name—you export production and import to a different cluster name for testing. (3) Moving data between systems or catalogs—EXPORT creates a portable backup; you transfer the sequential file and run IMPORT on the target system. (4) Restoring an alternate index or a catalog from backup. Do not use IMPORT to copy from a live VSAM file to another; use REPRO for that. Do not use IMPORT to read a dataset that was not created by EXPORT; the format is specific to EXPORT/IMPORT.

Syntax and Parameters

The general form of IMPORT is:

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  IMPORT -
    { INFILE(ddname) | INDATASET(dataset-name) } -
    OUTDATASET(output-dataset-name) -
    [ NEWNAME(newname) ] -
    [ INTOEMPTY ] -
    [ VOLUMES(volser [ volser ... ]) ] -
    [ PURGE | NOPURGE ] -
    [ ERASE | NOERASE ]
 

You must specify the input (INFILE or INDATASET) and the output (OUTDATASET). The rest are optional. The following table describes each parameter.

INFILE vs INDATASET

INFILE(ddname) means the backup dataset is allocated via a DD statement in your JCL; you give the DD name. Use INFILE when the backup is in a cataloged dataset that you reference with a DD (e.g. //BACKUP DD DSN=MY.EXPORT.BACKUP,DISP=SHR). INDATASET(dataset-name) means you give the catalog name of the backup dataset directly. Use INDATASET when the backup is in the default catalog or when the name will resolve. If the backup is in a user catalog, ensure JOBCAT or STEPCAT points to that catalog so the name resolves, or use INFILE with a DD that points to the backup.

OUTDATASET and NEWNAME

OUTDATASET is the name of the target VSAM object that will receive the restored data. It can be the same as the original name (restore in place) or a new name (restore to a different cluster). NEWNAME(newname) is an alternative or additional way to specify a new name for the restored object; behavior can vary by implementation. In either case, the restored cluster (or AIX) will be known by the name you specify. If you are restoring over an existing cluster, that cluster may need to be deleted first or IMPORT may replace it depending on options and implementation. Check your IDCAMS documentation. When restoring for testing, use OUTDATASET with a test name (e.g. MY.APPL.TEST.KSDS) so you do not overwrite production.

INTOEMPTY

INTOEMPTY indicates that the target is empty or is to be treated as empty for the import. Some implementations require INTOEMPTY when the target cluster does not exist (IMPORT will create it from the backup) or when the target exists but has no records. Using INTOEMPTY avoids accidentally appending imported data to an existing cluster that already has data. If you omit INTOEMPTY and the target has data, the behavior may be implementation-dependent (error or append). For a clean restore, specify INTOEMPTY when the target is empty or new.

IMPORT vs REPRO

REPRO copies records from a source dataset to a target dataset. Both source and target are typically already defined. REPRO does not create the target; you must DEFINE CLUSTER (or have a sequential output) first. EXPORT writes a special sequential backup that contains data plus catalog/structure information. IMPORT reads that backup and can recreate the VSAM object. So: use EXPORT to create a backup, and IMPORT to restore it. Use REPRO to copy data between two existing datasets (VSAM to VSAM, sequential to VSAM, or VSAM to sequential). The following table summarizes the difference.

Example: Restore a Cluster from Backup

Suppose you have an EXPORT backup in MY.APPL.EXPORT.BACKUP and you want to restore it to MY.APPL.RESTORED.KSDS. The target does not exist yet.

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  //RESTORE  EXEC PGM=IDCAMS
  //SYSPRINT DD SYSOUT=*
  //BACKUP   DD DSN=MY.APPL.EXPORT.BACKUP,DISP=SHR
  //SYSIN    DD *
    IMPORT INFILE(BACKUP) -
      OUTDATASET(MY.APPL.RESTORED.KSDS) -
      INTOEMPTY
  /*
 

If the backup were cataloged and you used INDATASET:

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  IMPORT INDATASET(MY.APPL.EXPORT.BACKUP) -
    OUTDATASET(MY.APPL.RESTORED.KSDS) -
    INTOEMPTY
 

Example: Restore with New Name and Volumes

Restore the same backup to a different name and place it on a specific volume:

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  IMPORT INFILE(BACKUP) -
    OUTDATASET(MY.APPL.TEST.KSDS) -
    INTOEMPTY -
    VOLUMES(TEST01)
 

Restoring Alternate Indexes and Catalogs

You can EXPORT and IMPORT alternate indexes and catalogs as well as clusters. For an AIX, the backup contains the AIX cluster and its data and index components. IMPORT restores the AIX; if the base cluster was also restored, ensure the AIX is restored after the base so the relationship is correct. For catalog export/import, follow your installation's procedures; catalog restore is a critical operation and may require specific options and order. See your IDCAMS and catalog documentation.

Key Takeaways

• IMPORT restores a VSAM object from a backup created by EXPORT. Use it for recovery or for moving data between systems.
• Specify input with INFILE(ddname) or INDATASET(dataset-name) and output with OUTDATASET(name). Use NEWNAME or OUTDATASET to restore under a different name.
• Use INTOEMPTY when the target is empty or new so the restore does not append to existing data by mistake.
• IMPORT is for EXPORT backups; REPRO is for copying between existing VSAM or sequential datasets.

Explain Like I'm Five

EXPORT is like putting your toys in a special box so you can move them or save them. IMPORT is like opening that box and putting the toys back—either in the same place or in a new place (new name). The box has to be the one EXPORT made; you can't use a different kind of box (another file format). INTOEMPTY means "the shelf where I'm putting them is empty," so you don't mix the restored toys with other ones already there.

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