The front and rear LEDs indicate drive status and activity (only the 2big and 5big have rear drive LEDs). This section describes the behavior of the LED indicators.

d2

Front LED Color	State
Blinking blue	Occurs as the device is booting; will cease once the drives are fully initialized
	Backup in progress
Solid blue	Drive working (read/write)
Blinking red	Temperature alert (first level)
	Power supply has been cut but power is still being supplied through the UPS
Solid red	Temperature alert (critic level) – the product will shut off
	Power supply has been cut and the UPS has run out of reserve power – the product will shut off

2big/5big

Front LED Color	Rear LED Color	State
Blinking blue	Activity LED for working disk(s) (until they are fully initialized)	Occurs as the device is booting; will cease once the drives are fully initialized
	Activity LED for working disk(s)	Backup in progress
	Blinking blue/red	RAID synchronizing; will cease once operation has concluded
Solid blue	Activity LED for working disk(s)	Drive working (read/write)
Blinking red	Activity LED for working disk(s)	RAID is degraded; data is intact but no longer protected from further failed disks
	Solid red for non-functional disk(s)
	Activity LED	Temperature alert (first level)
		Fan is not spinning
		Power supply has been cut but power is still being supplied through the UPS
Solid red	Activity LED for working disk(s)	Temperature alert (critic level) – the product will shut off
	Activity LED for working disk(s)	Power supply has been cut and the UPS has run out of reserve power – the product will shut off
	Solid red for non-functional disk(s)	RAID has failed and data has been lost
	Off in disconnected disk(s)	Disk(s) is/are disconnected