SAS Drive Activity LEDs: A Small Discovery

When Your Drives Go Silent

I recently bought SAS drives for the first time, stepping up from years of running SATA HDDs. I was excited for the reliability and performance, but immediately noticed something odd: the activity LEDs behaved in reverse - they were lit when idle and turned off during drive activity.

The Search for Answers

After some digging through forums, I found out, that this is normal behaviour for these drives. Fortunately, we can easily change that

The Fix

The solution is simple: use sdparm to enable the LEDs.

For a single drive, run:

sudo sdparm --set=RLM /dev/sdx

If you want the setting to persist after a reboot or power cycle, add --save:

sudo sdparm --set=RLM --save /dev/sdx

For multiple drives, a quick loop does the trick:

for i in {a..x}; do sudo sdparm --set=RLM --save /dev/sd$i > /dev/null; done

Without the --save flag, the setting will be lost after replugging or rebooting the drive.

Reverting the Change

If you ever want to turn the activity LEDs off again, just clear the setting:

sudo sdparm --clear=RLM --save /dev/sdx

Again, use --save if you want the change to stick after power cycles.