So that's not actually "safe". If you issue an insert in the default "fire and forget" mode and that insert causes an error (say a duplicate key violation), no

So that's not actually "safe". If you issue an insert in the default "fire and forget" mode and that insert causes an error (say a duplicate key violation), no exception will be thrown. Even with journaling on your code does not get an exception. Journaling is a method for doing "fast recovery" and flushing to disk on a regular basis. "Write Safety" is method for controlling how / where the data has been written. So these are really two different things.