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Resynchronizing the snapshot to your database

When you have finished using a clone database or want to refresh it, you can resynchronize it with the original database. This is also known as refreshing the snapshot volume or merging the split snapshot image back to the current database image. After resynchronizing, the snapshot can be retaken for backup or decision-support purposes.

There are two choices when resynchronizing the data in a volume:

• Resynchronizing the snapshot from the original volume. This option is explained in this section.
• Resynchronizing the original volume from the snapshot. This choice is known as reverse resynchronization. Reverse resynchronization may be necessary to restore a corrupted database and is usually much quicker than using alternative approaches such as full restoration from backup media.

Prerequisites

• You must be logged in as the Oracle database administrator.
• Before you can resynchronize the snapshot image, you must complete the steps in Summary of database snapshot steps, Validating a snapplan (dbed_vmchecksnap), and Creating a snapshot (dbed_vmsnap.
• If a clone database has been created, shut it down and unmount the file systems using the dbed_vmclonedb -o umount command. This command also deports the disk group if the primary and secondary hosts are different.

  See Shutting Down the Clone Database and Unmounting File Systems.

Usage Notes

• The dbed_vmsnap command can only be executed on the primary host.
• In a two-host configuration, the dbed_vmsnap command imports the disk group that was deported from the secondary host and joins the disk group back to the original disk group. The snapshot volumes again become plexes of the original volumes. The snapshot is then resynchronized.
• See the dbed_vmsnap(1M) manual page for more information.
• You cannot access the Database FlashSnap commands dbed_vmsnap, (dbed_vmchecksnap, and dbed_vmclonedb) with the SFDB menu utility.

 To resynchronize the snapshot image

• Use the dbed_vmsnap command as follows:

  $ /opt/VRTS/bin/dbed_vmsnap -S ORACLE_SID -f SNAPPLAN -o resync

In this example, the snapshot image is resynchronized with the primary database.

$ /opt/VRTS/bin/dbed_vmsnap -S PROD -f snap1 -o resync

dbed_vmsnap started at 2004-04-02 16:19:05

The option resync has been completed.

dbed_vmsnap ended at 2004-04-02 16:19:26

Now, you can again start creating snapshots.