ORA-01381: Dropping log string would leave less than two log files with block size string for instance string (thread string)
Cause: The database was migrated to use a specified log block size. Dropping all the logs specified would leave fewer than the required two log files with the specified block size per enabled thread.
Action: Either drop fewer logs or disable the thread before deleting the logs. It may be possible to clear the log rather than drop it.
