Today I stumbled upon some mysterious issue whilst trying to duplicate one database. I used the same process and same commands, which are worked fine on other systems. But, today the duplicate command gets hung while restoring spfile on one auxiliary instance.
I killed the RMAN session and started it all over again, but without success. Every time it gets stuck at the point, when the spfile should be restored. I lost maybe one hour, trying to figure it out, why it doesn’t work, and finally decided to search for any similar problems/solutions on My Oracle Support homepage. And I found it! It’s a bug: BUG 20721271 DUPLICATE FOR STANDBY FROM ACTIVE DATABASE HANGS WHILE RESTORING CONTROL FILE
The solution is to disable “Out Of Band Break“, which means to set the parameter DISABLE_OOB=on in the sqlnet.ora file. So, I set it and restarted the duplicate command – and it worked fine as it should!
More details in this MOS Note: RMAN active duplicate hanging on restore control file (Doc ID 2073604.1)