I have 4 databases all on four different machines, I want to configure RMAN for all the databases on a single machine. One of the database is a test DB. I would appreciate if some one can help me out in this.
Developing a backup strategy is important for your company data safty. I can give you hints to use for example in the company i work for and it is a very large scale company we use RMAN catalog and this catalog we register the databases with to keep the backup information in a safe location and in order to be able to determine the latest status in case of disaster "EG: the whole machine was down or crashed and you need to restore to a different machine".You can refer always to the catalog in these cases.
You need also to develop a backup scripts to backup the databases regularly .You need to set daily backup to backup the database every day and you need to backup the database every week which is known as full and incremental backups.
You will need to use a way to schedule those scripts to run in a cretin time like the crontab job .We are using semantic netbackup for example to schedule backups.
Please refer to the documentation and read the concept well as shown in the link below as the backup strategy and planing is important and very critical action you should care when designing in order to be able to recover when a major crash occur.
I agree with you but we do this with very large databases by using Rman image copy.If the database is 100 or 200 giga the backup will take 2 to 4 hours depending on the tape library and netbackup bandwidth.
if the database is 2 tera we cannot afford 2 days backup so we backup it using image copy and if a disaster occur we use switch copy.if you can take a backup of the image copy to a disk it will be cool and will offload the production.if you have a data guard you can offload the production and backup from it directly.