Recovery operations

This topic explains the types of recovery that you can perform with RUV.

Backout recovery operation

You can perform a backout recovery operation to roll back a data set to an earlier state. For example, when an application program updates a data set incorrectly or when an abend causes an incomplete update, the data set must be recovered to its previously known condition. The backout recovery operation uses the current copy of a data set and all before-image journal records that were created since the point-in-time specified for recovery (see the following figure). See Coding the RECOVER BACKOUT Statements for the command syntax.

The following figure shows a backout recovery process:

Forward recovery operation

After a data set becomes physically damaged, you can perform a forward recovery operation to update the data set from an earlier state to the current time or a specified time (see the following figure). See Coding the RECOVER BACKOUT Statements for the command syntax.

The following figure shows a forward recovery process:

Unit-of-Work recovery operation

A unit-of-work (UOW) recovery operation is a forward recovery that applies only completed transactions to the data set (see the following figure). The UOW recovery operation uses a backup of a data set and all after-image journal records that were created from the time the backup was made until the point in time specified for recovery. Updates that are part of an incomplete UOW are not applied to the current recovery and can be written to a separate output file. You can view this file to identify which transaction data was not applied to the recovery. The output data can also be used as input for a subsequent UOW recovery. See Coding the RECOVER BACKOUT Statements for the command syntax.

The following figure shows a UOW recovery process: