An error occurred with the function of one of more FRUs: the disk shelf, disk drives, IOM12/IOM12B modules, or power supplies. Check event messages to determine corrective action to take. Power cycle the disk shelf for the shelf ID. The LEDs on the disk shelf front operator display panel indicate whether your disk shelf is functioning normally or there are problems with the hardware. The following table describes the three LEDs on the operator display panel used in DS460C, DS224C, and DS212C disk shelves: One or more power. Monitoring the Disk Shelf About this chapter This chapter describes how to monitor the disk shelf from the error messages displayed on the console that is connected to the system and identifies the location of the various LEDs on the disk shelf. The light curtain is most often blocked or interrupted as the doors are opening or closing or the tray is moving into or out of the.