RESTORE SYSTEM

The RESTORE SYSTEM online utility invokes z/OS® DFSMShsm to recover a Db2 subsystem or a data sharing group to a previous point in time. To perform the recovery, the utility uses data that is copied by the BACKUP SYSTEM utility.

Requirement: All data sets that are recovered with RESTORE SYSTEM must be SMS-managed.

The RESTORE SYSTEM utility can be run from any member in a data sharing group, even one that is normally quiesced when any backups are taken. Any member in the data sharing group that is active at or beyond the log truncation point must be restarted, and its logs are truncated to the SYSPITR LRSN point.

You can specify the SYSPITR LRSN point in the CRESTART control statement of the DSNJU003 (Change Log Inventory) utility. Any data sharing group member that is normally quiesced at the time the backups are taken and is not active at or beyond the log truncation point does not need to be restarted.

By default, RESTORE SYSTEM recovers the data from the database copy pool during the RESTORE phase and then applies logs to the point in time at which the existing logs were truncated during the LOGAPPLY phase. The RESTORE utility never restores logs from the log copy pool.

Restriction: RESTORE SYSTEM does not restore logs; the utility only applies the logs. If you specified BACKUP SYSTEM FULL to create copies of both the data and the logs, you can restore the logs by another method.

Output:

Output for RESTORE SYSTEM is the recovered copy of the data volume or volumes.

Authorization required

To run this utility, you must use a privilege set that includes installation SYSADM authority.

Execution phases of RESTORE SYSTEM

The RESTORE SYSTEM utility operates in the following phases:

Phase: Description
UTILINIT: Performs initialization and setup
RESTORE: Locates and restores the volume copies if the LOGONLY option is not specified
LOGAPPLY: Applies the outstanding log changes to the database
UTILTERM: Performs cleanup