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Recovering a database using a Storage Checkpoint

Since Storage Checkpoints record the before images of blocks that have changed, you can use them to do a file-system-based storage rollback to the exact time when the Storage Checkpoint was taken. You can consider Storage Checkpoints as backups that are online, and you can use them to roll back an entire database, a tablespace, or a single database file. Rolling back to or restoring from any Storage Checkpoint is generally very fast because only the changed data blocks need to be restored.

Some database changes made after a Storage Checkpoint was taken may make it impossible to perform an incomplete recovery of the databases after Storage Rollback of an online or offline Storage Checkpoint using the current control files. For example, you cannot perform incomplete recovery of the database to the point right before the control files have recorded the addition or removal of datafiles. To provide recovery options, a backup copy of the control file for the database is saved under the /etc/vx/SFDB/$ORACLE_SID/checkpoint_dir/CKPT_NAME directory immediately after a Storage Checkpoint is created. You can use this file to assist with database recovery, if necessary. If possible, both ASCII and binary versions of the control file will be left under the /etc/vx/SFDB/$ORACLE_SID/checkpoint_dir/CKPT_NAME directory. The binary version will be compressed to conserve space. Use extreme caution when recovering your database using alternate control files.

Suppose a user deletes a table by mistake right after 4:00 p.m., and you want to recover the database to a state just before the mistake. You created a Storage Checkpoint (Checkpoint_903937870) while the database was running at 11:00 a.m., and you have ARCHIVELOG mode enabled.

 To recover the database using a Storage Checkpoint

1. As root, freeze the VCS service group for the database

   # hagrp -freeze Service_Group

2. Ensure that the affected datafiles, tablespaces, or database are offline.
3. Use storage rollback to roll back any datafiles in the database that contained the table data from the Storage Checkpoint you created at 11:00 a.m.
4. Start up the database instance if it is down.
5. Unfreeze the service group

   # hagrp -unfreeze Service_Group

6. Use recover database until cancel, recover database until change, or recover database until time to re-apply archive logs to the point before the table was deleted to recover the database to 4:00 p.m.
7. Open the database with alter database open resetlogs.
8. Delete the Storage Checkpoint you created at 11:00 a.m. and any other Storage Checkpoints created before that time.
9. Create a new Storage Checkpoint.