Standby Database: Restore and Recovery

Use

This section describes what you need to do in the event of a failure with the Oracle Standby Database.

Activities

If the production database fails, you can do one of the following:

·        Switch to the standby database, which now becomes the production database

If you switch to the standby database, be sure to perform backups as described below in "Control File Backup and Complete Online Backup After a Switch."

After you have fixed the problem on the previous production database, you can do one of the following:

Ў        Stay with the swapped configuration

This means that you continue production operation on the previous standby database. In effect, you have swapped the configuration, with the previous production database becoming the standby database.

Ў        Resume the original configuration

This means that you switch back to the previous production database, to resume the configuration from before the failure. For more information, see "Resuming the Original Configuration after a Switch" below.

Which option you choose depends on whether the production and standby databases are equivalent in terms of processing power. Often, the standby database is less powerful, in which case it makes sense to switch back to the original production database as soon as possible.

·        Fix the problem and continue on the production database. If necessary, restore and recover the database with the redo log files, if available.

Control File Backup and Complete Online Backup After a Switch

If the production database fails, you can do one of the following after a takeover, you should back up the control file immediately. Otherwise, you cannot recover the standby database at all. For example, you can enter the following command to do this:

brbackup -m 0 -t online

For more information, see -m|-mode.

We then strongly recommend you to perform a complete online backup as soon as possible. For example, you can enter the following command to do this:

brbackup -f m all -t online

For more information, see -f|-fillup.

This is the only way to make sure that the standby database can be recovered, if necessary.

Be sure to perform this operation whenever you switch production from one database to another.

Resuming the Original Configuration After a Switch

To recreate and configure a production database after a switch, you can use BRBACKUP to perform an offline backup of the current production database (that is, the database that was functioning as a standby before the switch). To do this, set:

backup_type = offline_stop

For more information, see backup_type.

After the backup, you directly switch the database to mount-standby state, so it can resume the role of the standby database. After a restore on the production database, this can resume its role as production database. If you want to set it up in one step (that is, without a restore), you also set one of the following:

backup_dev_type = disk_standby|stage_standby

stage_copy_cmd = rcp|ftp|scp

For more information, see backup_dev_type or stage_copy_cmd.