About Integrating VSS with Third-Party Requester Applications

Oracle VSS writer allows third-party requester applications to control the behavior of recovery and backup sessions.

Third-party requester applications use VSS API setBackupOptions or setRestoreOptions to pass an appropriate string to the writer. The writer uses getBackupOptions or getRestoreOptions to get the string set from the requester to perform the pre or post backup and restore actions.

Running Writer Control Commands

The writer control commands are applicable to all the restored components during the postrestore phase.

The format is as follows:

OP1=CMD1, OP2=CMD2, . . .

Run the commands in the following sequence:

  1. POST_WTRCMD=NORECOVER

    This command instructs the writer to not perform any postrestore recovery activities defined in the default postrestore recovery operations for the restored component. Otherwise, the postrestore phase default actions are performed.

  2. POST_RMANCMD=cmdstr

    This command instructs the writer to run specific RMAN commands, instead of the default operations, after the current operation.

  3. PRE_SQLCMD=cmdstr

    This command instructs the writer to run specific SQL commands in OnPrepareBackup or OnPreRestore callback, before performing any other validations. The command is used to stop MRP on a standby database before VSS snapshot is created or to shut down database instance creating a cold backup of the database.

  4. POST_SQLCMD=cmdstr

    This command instructs the writer to run specific SQL commands in PostSnapshot or PostRestore callback. This command is used to restart MRP on standby database after VSS snapshot is created or to restart the database instance after the cold backup of the database is performed.

Controlling Commands for Database or All Tablespaces Component

The POST_WTRCMD=UNTIL_SNAPSHOT command instructs the writer to perform recovery to the snapshot creation time.

Run the following command:

POST_WTRCMD=UNTIL_SNAPSHOT

This command instructs the writer to perform recovery to the snapshot creation time. The writer extracts the system change number of the redo logs stored in the database component and performs recovery until the system change number.