Trouble Shooting Promise Pegasus Thunderbolt Raid Systems

How to Reformat Promise Pegasus System after a hard drive dies and you get the red light of death.

I have 2 Promise Pegasus Systems and I have replaced and reformatted the hard drives a couple of times, however this last time I did it I could not remember how to do this. After looking on the internet for hours I could not find anything on this. Just when I was about to give up I found this awesome video on how to do this. It is super simple and takes a couple of minutes at most. The video below will show you how to reformat a hard drive after it dies and you replace it. If you have the RED light issue please read below.

Promise Pegasus RED Light Fix

What happens when you get the red power button and all your drives are RED. If this is happening to you, do not worry. What you have to do is simple. Here are a few steps to get you back up and running.

The first thing you need to do is open up Promise Utility.

From the menu bar Click on Promise utility then -> Check for updates. – It would prompt for updating the firmware, update the firmware. (you might have to do this a few times to get caught up to the current update).  After the update, choose reboot & restart the unit.

This should fix the issue and you should be back up and running. If this does not fix it, you can do it via terminal.

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On the Mac, open the Terminal app and run: (just copy and paste and press enter) To open terminal go to the search bar on the top right corner.


This will open the Promise Utility. Now type the following: (copy and paste) If you only have one drive dead they just type that particular line. If all are dead copy and paste all lines. Hit enter.

phydrv -a online -p 1
phydrv -a online -p 2
phydrv -a online -p 3
phydrv -a online -p 4

If you have the R6 you will need to add the following commands in order to force drives 5 & 6 online –

phydrv -a online -p 5
phydrv -a online -p 6

After you force the drives online reboot the RAID and you should be good to go. If one of your drives is dead, simply replace the hard drive and follow instructions on the video below.

Reformat Promise Pegasus

How do you format a new hard drive in your Promise Pegasus System? Watch the video and follow along.

If this fixed your unit please leave a comment below. If you have something to add about your Pegasus system please add on the comments below.