Originally posted by julian
Not on disk. They will go to the same directory/mount point anyway. And there is not much point of that.

If you are backing up to tape you can configure the media manager and RMAN so that the copies of the pieces are written to separate devices.

See Note 70038.1.
Below in an excerpt from Note 70038.1. Now who in the real world can afford to allocate just one channel to achieve this redundancy?! It is kinda pointless.


Creating the backup

It is desirable to write backups to separate devices in order to achieve redundancy. This is achieved by specifing 'set duplex' to the number of available devices and allocating just one channel.

For example, to create 3 copies of the same database backup into 3 separate devices:
1. Ensure that the LSM server parallelism is set to at least 3.
2. Run the following RMAN script:
run { set duplex=3; allocate channel dup_channel type 'sbt_tape'; backup database; }