Oracle RAC standby - standby redo log configuration

Question

With an Oracle RAC standby DB where the primary has 2 threads of 4 groups of online redo logs, should the standby DB have 2 threads of 5 groups each? Or is just one additional group in one of the threads enough? Oracle recommends an extra group for standby's but I'm not sure if that means per thread or not.

I just want to clarify what the Oracle standard is here. Many thanks.

Answer 1

Yes. One additional group for each thread.

Minimally, the configuration should have one more standby redo log file group than the number of online redo log file groups on the primary database. However, the recommended number of standby redo log file groups is dependent on the number of threads on the primary database. Use the following equation to determine an appropriate number of standby redo log file groups:

(maximum number of logfiles for each thread + 1) * maximum number of threads

Reference: https://docs.oracle.com/cd/B19306_01/server.102/b14239/create_ps.htm#i1225703

Note: Make sure to create standby redo logs on both standby database and primary database.