Urgh. I had a RAID 6 reshape on my NAS that was projected to take 28 days to complete, I kid you not. It was stuck at an abysmal 4MB/s transfer rate. Here’s how to unblock it. First, follow all the advice on general raid speedups – assuming md2 is your RAID device and you need to replace sd[DEVICE] below with the correct block devices that constitute the array: This is all common advice that it is easy to find.