Restoring from a snapshot backup

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Follow the steps to restore an Oracle database. In a case where a control file copy was stored in the data volume group or data disk group, follow the steps to recover the current copy of the control file.

Before you begin

Ensure that the following requirements are met:

The redo logs for the database are in a disk group that is not shared with any Oracle data files.
The Oracle RAC data files are stored on a supported storage system.

Confirm with IBM FlashSystem storage administrator that the host location refers to the backup site.

Execute the lshost command.
Figure 1. Confirming site location
The output indicates that the host location (location_system) refers to the backup site.
If the location of the host is different than the backup site, issue the following commands from any site:
```
# chhost -location <site-2-name> <hostname>
```
Refer IBM FlashSystem documentation for more details.
If you want to restore the snapshot backup from site2, issue the following command from any site, before restore operation:
```
# chhost -location <site-2-name> <hostname>
```
Note: Only supported on the AIX platform.

About this task

After the snapshot restore process completes, you can start the recovery of the restored RAC database. In the example that is used, the database is called MYDB.

Procedure

Stop the database that is to be restored. Log on to the production server with the Oracle RAC instance owner user ID.

srvctl stop database -d MYDB

To find an existing backup ID, type the following command: acsora -f inquire.
Restore a snapshot backup. Choose one of the following methods:
- Restore the last snapshot backup by specifying the command,
```
acsora -f restore 
```
- To restore an older snapshot backup, specify the backup ID of that backup as follows:
```
acsora -f restore -b backup ID
```
  where the backup ID is the ID of the snapshot backup that you want to restore.
After the snapshot restore process completes, you must recover the database. Choose one of the following recovery types:
The recovery type is specified in the profile file. For more information about recovery types, see DATABASE_CONTROL_FILE_RESTORE in ORACLE.
- If DATABASE_CONTROL_FILE_RESTORE YES is specified in the IBM® Storage Protect Snapshot profile file, an incomplete recovery is needed.
- If DATABASE_CONTROL_FILE_RESTORE NO is specified in the IBM Storage Protect Snapshot profile file, a complete recovery is needed.
Tip: The steps for advanced recovery follow:
If a control file exists in the data volume group or data disk group, and it was not restored, there will be inconsistent copies of the control file after the snapshot restore operation finishes. To restore the control file copy that was overwritten by the restore operation from a current copy, follow these steps:
1. Start the instance without mounting the database by entering the following command:
  
  SQL> startup nomount
2. Use RMAN to restore a current copy of the control file that is not part of the data disk group, and is not restored.
  
  RMAN> restore controlfile from '<control_file_copy_name>'
3. Mount the database, and recover the database for a complete recovery.
```
SQL> alter database mount;
SQL> recover database;
```
4. Open the database if you want to continue working with the fully recovered database.
  
  SQL> alter database open;

Results

If you restored the control file from a current copy, the control file in the data disk group is overwritten to that current version.

Important: On some storage system types, the snapshot restore requires sufficient available space on the target storage pool in order to restore the necessary volume. If there is not enough storage space available, you can increase the capacity on the requested storage pool, or free up some capacity. Check the message for the exact amount of storage space that is required.