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vandeepu@gmail.com asks:

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Hello all, first of all, I wanted to tell you that this is not a challenge. I have tried to find a solution for my below question, but I couldn't. I asked for help on some forums like orafaq and OTN but no one helped me. I am expecting atleast some help here. I have set up a single instance standbys for rac databases. Now, I need to offload the backups from the primary on to the standbys. I learnt a few points to achieve this. 1. cancel managed recovery 2. connect to target(standby) and catalog and backup the standby 3. put standby in managed recovery mode. I think following these steps, I can restore primary(?). Now, My question is, how can I use these standby backups to clone/refresh databases? I tried it by connecting to target(primary), catalog and auxiliary but rman is using the primary backups instead of standby's to refresh the auxiliary database. If anyone can help me with their suggestions that would be great. I have a 11202 oracle on a linux box. Few followups to my question at this link http://www.orafaq.com/forum/t/176696/0/

Answer

The answer to your first question - whehter it is a right way of doing the standby and whether you can back up off standby - is ys, it is. Just remember that if you are using block change tracking, then BCT will not work in standby.
Second question - I am not sur I understand it completely. Are you taking backups from two different sources - standby and primary? Well, why? The backup from standby can be used for restoring primary database; so there is no real advantage of backing up primary.
But if you are doing it for some reason, you will notice that the tags will be different for the backups. When you ar refreshing a new database from this backup, you can explictly use the tag for standby.
 
On why it is doing so, I think the SCN number of the primary is always ahead. During restore, RMAN will always choose the backups with the highst SCN so that there will be minimum archivelog to be applied.
 
Hope this helps.
 
Arup Nanda