Backing up and Recovering Data Sets

ISMF uses DFSMShsm and DFSMSdss to help you make, store, and recover backup copies of your data sets. From the data set list, you can perform the following tasks:

Create backup versions of a single data set or group of data sets.
Control the frequency of backup and the number of backup versions made.
Delete backup versions that you no longer need.
Recover backup versions of data sets that you have stored on tape, DASD, or a mass storage volume.

Table 1 summarizes the DFSMShsm and DFSMSdss commands that ISMF uses for backup and recovery.

Table 1. Summary of Commands for Backup/Recovery of Data Sets
Task	Function	Scope	Action
Create a backup version of a data set.	HBACKDS	Single data set	Creates a backup version of a data set. Performed in the foreground by DFSMShsm.
Create backup versions of data sets.	DUMP	Single data set, group of data sets, or volume	Dumps data sets to tape, DASD, or mass storage volumes. Performed in the background by DFSMSdss.
Control the frequency of backup and number of backup versions.	HALTERDS	Single data set	Changes the number of backup versions of a data set and controls the frequency of backup. Performed in the foreground by DFSMShsm.
Delete a backup version of a data set.	HBDELETE	Single data set	Deletes backup version of a data set. Performed in the foreground by DFSMShsm.
Delete migrated version of a data set.	HDELETE	Single data set	Deletes a migrated version of a data set. Performed in the foreground by DFSMShsm.
Recover the backup version of a data set.	HRECOVER	Single data set	Recovers a backup version of a data set. Performed in the foreground by DFSMShsm.
Restore dumped data set or DASD volume.	RESTORE	Single data set, group of data set, or single volume	Restores data dumped by DFSMSdss. If the data was compressed, it is expanded to its original form. Performed in the background by DFSMSdss. This command can be entered on the Data Set Selection Entry Panel and the Data Set List Panel. It can be entered on the Volume List Panel as a line operator only.
Restore an unlisted dumped data set.	RESTORE DATASET	Single data set	Restores an unlisted data set dumped by DFSMSdss. If the data was compressed, it is expanded to its original form. Performed in the background by DFSMSdss. This command can be entered on the command line of the Data Set List Panel or the Data Set Selection Entry Panel.

Creating Backup Versions of Data Sets or Volumes

ISMF provides two ways to create backup versions of your data sets: the HBACKDS line operator or the DUMP line operator or list command.

HBACKDS can be used against individual entries in a data set list. The data set must be cataloged. In a DFSMShsm environment, backing up data sets can be done automatically. However, if you do not want to wait, you can request an immediate backup using the HBACKDS line operator. When you use HBACKDS, DFSMShsm creates and stores a backup version of the specified data set. You do not need to identify the volume for DFSMShsm to store the data set. DFSMShsm chooses a volume.

HBACKDS is performed in the foreground. When you enter the line operator on the data set list, ISMF displays the HBACKDS Entry Panel. On the entry panel you can indicate whether you want to wait for the command to execute or return immediately to the list panel. If you choose to wait, ISMF displays the HBACKDS Entry Panel until the backup version of the data set has been created.

DUMP can be used for a single data set, a group of data sets, or a volume. It is performed as a background job by DFSMSdss. If you enter DUMP in the line operator field, DFSMSdss places a backup copy of a single data set or volume on the media you choose: tape, DASD, or a mass storage volume. If you enter DUMP as a list command on the command line of the data set list, DFSMSdss makes backup copies of each data set in the list.

When you enter DUMP as either a line operator or list command, ISMF displays the associated data entry panels. On the data entry panels, you can specify the following options:

Dump single volume, multivolume, and VSAM data sets.
Dump to tape or DASD.
Specify allocation values for the new data set.
Determine the disposition of the output data set when the dump is successful or if it is unsuccessful.
Dump multiple copies of data sets.
Automatically compress the data when it is dumped.
Specify a maximum number of attempts DFSMSdss should make to dump the data set and the number of seconds between each retry
Dump the data set even if it is being used by another program.
Use dynamic allocation instead of enqueue to coordinate the use of the data set.
Allow other programs read access to the data set while it is being dumped.
Dump all allocated space or only space that has actually been used.
Stop the DUMP after the first I/O error or after 100 errors.
Specify the amount of I/O buffering DFSMSdss should use.
Reset change indicators in the DSCB for all data sets successfully dumped.

Many of the previous DUMP capabilities also apply to the entry panel displayed during a Volume Application. In addition, when performing tasks against volumes, you can choose between a physical and a logical dump, and you can specify from which volumes allocated space is dumped.

The online HELP explains the individual fields on the DUMP data entry panels and the different options you have when you use DUMP. ISMF supplies defaults for many of these options.

Controlling the Number of DFSMShsm Backup Versions and the Frequency of Backup

HALTERDS allows you to control the number of backup versions DFSMShsm maintains of a DFSMShsm-managed data set. With HALTERDS you can also change the default value for the frequency of creating backup versions. When you enter the HALTERDS line operator, ISMF displays the HALTERDS Entry Panel primed with the data set name. On the entry panel, you can specify how often you want DFSMShsm to create backup versions of the data set and the number of backup versions you want to keep. HALTERDS is performed in the foreground. You cannot use this line operator in last-use mode. It works only in normal mode. This command cannot be used on SMS-managed data sets that are controlled by the data set's management class parameters.

Deleting Backup Versions of Data Sets

Use HBDELETE when you want to erase backup versions of data sets that have been made using DFSMShsm. When you enter the HBDELETE line operator, ISMF displays the HBDELETE Entry Panel for the data set you indicated. You can use the entry panel to delete all the backup versions of the data set or you can delete only specific versions by number. HBDELETE works in normal mode and is performed in the foreground by DFSMShsm.

Recovering Backup Versions of Data Sets and Volumes

There are two ways to recover backup versions of data sets. You can use the HRECOVER line operator for data sets backed up by using HBACKDS. You can also use the RESTORE line operator or list command for data sets backed up by using DUMP. The RESTORE line operator can also be used for volumes.

HRECOVER recovers a backup version of an individual cataloged data set from a DFSMShsm-managed volume. When you enter HRECOVER, ISMF displays the HRECOVER Entry Panel. The entry panel is primed with the name of the data set you want to recover. On the entry panel, you can specify the generation number or date of the backup version you want to recover as well as the serial number of the target volume. You can also choose to rename the data set as it is recovered or to replace the existing data set with the backup version.

HRECOVER is performed in the foreground by DFSMShsm. You can wait for the data set to be recovered before you return to the list panel. If you choose to wait for completion, the HRECOVER Entry Panel is displayed until the command has been performed. Otherwise, you return to the list immediately.

RESTORE allows you to restore data sets dumped by DFSMSdss to a DASD volume. RESTORE is performed in the background. When you enter RESTORE, ISMF displays data entry panels for you to complete. The information you provide allows you to perform these tasks:

Restore multivolume data sets.
Restore VSAM data sets.
Rename data sets as they are restored.
Replace the original data set with the dumped data set.
Catalog data sets as they are restored.
Specify target volumes.
Retain RACF® protection for restored data sets that were originally RACF-protected.
Specify a maximum number of attempts DFSMSdss should make to restore the data set and the number of seconds between each retry.
Determine the disposition of the original data set when the RESTORE command is successful or unsuccessful.
Restore the data set even if it is being used by another program.
Restore data sets that were allocated as unmovable.
Use dynamic allocation instead of enqueue to coordinate the use of the data set.
Allow other programs read access to the data sets while they are being restored.
Verify the data after the RESTORE.
Stop the RESTORE after the first I/O error or allow all errors.

You can restore an individual data set or a list of data sets. To restore an individual data set, use the RESTORE line operator or the RESTORE DATASET command. To restore a list of data sets, use the RESTORE or the RESTORE LIST list commands.

When you enter RESTORE in the line operator field of the list panel, ISMF recognizes it as a line operator and restores the corresponding data set. RESTORE DATASET also restores an individual data set, but unlike the RESTORE line operator, the data set you want to restore need not appear on the list panel. For example, you may want to restore a data set that has been deleted. You can enter the RESTORE DATASET command on the command line of either the Data Set Selection Entry Panel or the Data Set List Panel. When you enter RESTORE DATASET, ISMF displays the first page of the Data Set RESTORE Entry Panel so that you can supply the name of the dumped data set you want to restore.

On the Data Set Selection Entry Panel, RESTORE is also an acceptable form of the RESTORE DATASET command. When you enter RESTORE on the command line of the Data Set Selection Entry Panel, ISMF assumes you want to restore an individual data set. You can also specify RESTORE on the DASD Volume Selection Entry Panel. You can select either a logical or a physical RESTORE and you will see a confirmation panel if you choose to replace the volume serial number.

RESTORE LIST restores an entire list of data sets that have been dumped by DFSMSdss. You enter the RESTORE LIST command on the command line of the Data Set List. RESTORE is also an acceptable form of the RESTORE LIST command. When you enter RESTORE on the command line of the Data Set List, ISMF assumes that you want to restore the entire list of data sets. RESTORE LIST is not a valid command on the Data Set Selection Entry Panel.