Oracle : Ошибка ORA-38855

"cannot mark instance %s (redo thread %s) as enabled"
*Cause: The standby switchover or failover operation failed because it
needs to mark an instance (redo thread) as enabled. However, it
had less than 2 online redo logs, which prevented it from being
*Action: Add more logfiles to the specified instance and retry the command.

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