Good luck with that. I hope you don’t get the problems I had after setting it to mirror - about 40 hours before the thing became ‘normally responsive’.
That seems really slow - but others have experienced very slow/variable rates too.
Mine were very variable, and usually horrible whilst rebuilding. They now seem to have settled but seem slow - a recent test on a 2.8gb single mp3… 2 minutes forty seconds when directly connecting the LD to my Mac, or ethernetting my Mac to the router to which the LG is connected. Five minutes twenty seconds by wifi.