Veritas Storage Foundation 5.0 for Oracle RAC Configuration Guide Extracts for HP Serviceguard Storage Management Suite, Second Edition, May 2008

Using Storage Checkpoints and Storage Rollback
Guidelines for Oracle Recovery
Chapter 4
51
Guidelines for Oracle Recovery
For optimal Oracle recovery, follow these guidelines:
• Back up all control files before storage rollback in case the subsequent Oracle
recovery is not successful. Oracle recommends that you keep at least two copies of
the control files for each Oracle database and that you store the copies on different
disks. It is also a good idea to back up the control files before and after making
structural changes to databases.
NOTE The dbed_ckptcreate command automatically saves control file and log information
when you create a Storage Checkpoint.
• Make sure that the control files are not rolled back.
A control file is a small binary file that describes the structure of the database and
must be available to mount, open, and maintain the database. The control file stores
all necessary database file information, log file information, the name of the
database, the timestamp of database creation, and synchronization information,
such as the Storage Checkpoint and log-sequence information needed for recovery.
Rolling back the control file will result in an inconsistency between the physical
database structure and the control file.
NOTE If your intention is to roll back the database to recover from structural changes that
you do not want to maintain, you may want to use the backup control file that was
created by the dbed_ckptcreate command. The backup control file is located in the
directory $VXDBA_DBPATH/$ORACLE_SID/checkpoint_dir/CKPT_NAME.
• Make sure that all archived redo logs are available.
A database backup with online and archived logs is required for a complete database
recovery. Query V$ARCHIVED_LOG to list all the archived log information and
V$ARCHIVE_DEST to list the location of archive destinations.
To restore the necessary archived redo log files, you can query V$LOG_HISTORY to list
all the archived redo log history or query V$RECOVERY_LOG to list only the archived
redo logs needed for recovery. The required archived redo log files can be restored to
the destination specified in the LOG_ARCHIVE_DEST parameter or to an alternate
location. If the archived redo logs were restored to an alternate location, use the
ALTER DATABASE RECOVER ... FROM statement during media recovery.
• After storage rollback, perform Oracle recovery, applying some or all of the archived
redo logs.
NOTE After rolling back the database (including control files and redo logs) to a Storage
Checkpoint, you need to recover the Oracle database instance. Rolling the database
forward is not supported; that is, you cannot apply archived redo logs.
To perform a complete media recovery:
SET AUTORECOVERY ON;
RECOVER DATABASE;