We had a similar issue, albeit with a different version of DataONTAP. We had the blink on and turned it off, but the blinking didn't stop. The disk was listed as unassigned. We manually assigned the new disk as a spare and the blinking stopped. We had also tried removing and reinserting the drive but that didn't stop the blinking. Again, it was a different version (8.3.2) but it may be your issue.