You administer a RAC database that currently runs on a four-node cluster but which has three instances.
Which two statements are always true about redo logs for this RAC database? (Choose two.)
A.
A thread of redo must be created before starting a fourth instance if a thread is not already available.
B.
A thread of redo must contain at least two log groups before it can be enabled.
C.
A redo log group added using ALTER DATABASE ADD LOGFILE without the INSTANCE clause is added to each instance.
D.
All the instances must have the same number of redo log groups and each group must have the same number of redo log members.
E.
A thread of redo is automatically dropped when as instance is removed from a RAC database by using SRVCTL.
B , C
A. Oracle Clusterware automatically enables a thread of redo
D. Not needed same number of redo logs
E. Not automatic, need to manually disable thread.
C: wrong.
If you do not specify the instance when adding the redo log group, then the redo log group is added to the instance to which you are currently connected.
Source : D81250GC10.
Correct A,B
source: RAC admin 4-11
A.
A thread of redo must be created (this will be automatically enable by Oracle Clusterware, the thing here is that it must be enable)
Agree A,B