Databases Reference
In-Depth Information
Choose the data files contained within one backup set to be restored through one channel. In this example I am
assuming that the data files 1, 3, and 5 are in one backup set and 2, 4, and 6 are in the other. If you decide to restore the
entire database, use:
connect target /
run {
allocate channel c1 type disk connect rman/secretsauze@rman1;
allocate channel c2 type disk connect rman/secretsauze@rman2;
restore database;
}
How It Works
RMAN channels are nothing but sessions. When you allocate a channel, by default it creates the sessions in the
instance running on that node.
Normally you allocate a channel as follows:
allocate channel c2 type disk;
But you can choose instead to specify the
connect
clause in the
allocate channel
command:
allocate channel c2 type disk connect rman/secretsauze@rman2;
When you take this approach, sessions will be connected as specified in the connect string—rman2, in this case.
Since rman2 points to the service name RMAN2, and since that service runs on node 2, the session will be created on
instance 2. The RMAN command can be executed in node 1, but channel c2 will still be created in node 2.
The
(datafile <Datafile#> channel <ChannelName>)
syntax in restore command forces the restores through
the named channel, and consequently through the node on which the channel is created. That is how the solution
example directs different files to be restored by different nodes.
Backing Up a RAC Database to Tape
Problem
You have an RAC database with multiple instances. While backing up this database to tape, you want the tape
channels to be open and running on all the nodes of the cluster.
Solution
Follow steps 1 through 5 of Recipe 23-3. After that, there are two options for accomplishing your objective. In both the
options, we have assumed a NetBackup environment for tape backup.
