Dell Precision 7920 Tower Owner's Manual page 126

NOTE: If the hard drive is in the Advanced Host Controller Interface (AHCI) mode, the status LED indicator does not
turn on.
NOTE: Drive status indicator behavior is managed by Storage Spaces Direct. Not all drive status indicators may be used.
Table 22. Hard drive indicator codes
Hard drive status indicator code
Flashes green twice per second
Off
Flashes green, amber, and then turns off
Flashes amber four times per second
Flashes green slowly
Solid green
Flashes green for three seconds, amber for three seconds, and
then turns off after six seconds
126 Troubleshooting
Condition
Identifying drive or preparing for removal.
Drive ready for removal.
NOTE: The drive status indicator remains off until all drives
are initialized after the system is turned on. Drives are not
ready for removal during this time.
Predicted drive failure.
Drive failed.
Drive rebuilding.
Drive online.
Rebuild stopped.