Databases Reference
In-Depth Information
The first step in a restore and recovery process is to determine what files have experienced media failure. You can
usually determine what files need to be restored from three sources:
•
Error messages displayed on your screen, either from RMAN or SQL*Plus
•
Alert.log file and corresponding trace files
•
Data dictionary views
■
See Chapter 20 for details on using the Data recovery advisor to determine how to restore and recover
your database.
Note
Once you identify which files are damaged or missing, you need to determine what steps to take to restore and
recover. Table
11-2
contains general guidelines on what to do when presented with a media failure. You'll have to
tailor these guidelines to your type of failure and then find the applicable recipe for specific instructions.
Table 11-2.
Where to Look for Restore and Recovery Instructions
Files Needing Media Recovery
Action
Chapter/Recipe
Data files with all required redo
available
Complete recovery
Chapter 11
Data files without all required redo
available
Incomplete recovery
Chapter 12
Control files
Restore control file
Chapter 10
Online redo log files
Combination of clearing and/or re-creating
online redo log files and possibly
performing incomplete recovery
Chapter 14
Spfile
Restore spfile
Recipe 11-14
Archived redo log files
Restore archived redo log files from another
location or from RMAN backup
Recipe 11-15
Control file has no information
about RMAN backup piece
Use the
catalog
command to populate control
file with RMAN backup metadata
Recipes 11-18 and 11-19
Need to restore a container root or
pluggable database
Restore at root or pluggable database level
Recipe 11-20
Accidentally dropped table or
deleted data
Flash back to before drop, SCN, or RMAN restore
table to a point in time
Chapter 13
How It Works
When faced with a media failure, you need to have a good understanding of your backup strategy and how that
will enable you to restore and recover your database. You should periodically test your backups so that you can
confidently recover your database when faced with a media failure (see Recipe 11-21 for details on manually restoring
and recovering your database to a different server). When you initially create your backup strategy, you should also
design a corresponding restore and recovery strategy. A sound backup strategy should minimize your risk of losing
data and minimize the downtime of your database.
