Rebuild New Harddrive on RAID 5 (Pegasus 2 R4) without loosing data on other HDs

  • Last Post 01 October 2017
Remo Kobler posted this 18 December 2016

HI - I installed Sierra OS which did not recognized my Pegasus 2 R4 system. after many calls to Apple and then, some technical support with Promises they informed me that my #1 HD was failing and that I should replace it.

So, now I have purchased and installed the new HD into my Pegasus 2 R4 system, and have it plugged into my Mact with Seirra OS. The system needs to recognized the new HD and I do not know how to install the system so the RAID 5 is working without loosing the data on the other 3 HDs that are still working well in my system??

Can someone please give me step by step instructions to rebuild this new HD in the RAID 5?

I do not want to erase the other 3 HDs since they have my Data on them, and simply want the new HD to be recognized as part of the RAID 5 so, I can continue working as normal.

I was going to try follow the Wizard to set it up, but am afraid that I may do it incorrectly, and I also need to ensure that the HD are set up as "Mac OS Extended (Journaled)".

If you can please provide step by step instructions.

Thank you and appreciate your help!


Attached Files

Order By: Standard | Latest | Votes
Raghuraman Kannan posted this 18 December 2016

Hi Remo,

Please follow the below steps to start the rebuild on that drive.

- Open Promise utility and unlock it.

- Click on "Physical Drive" list in the Utility and make sure the replacement drive is showing up in the list .

- The status of the new drive should be "Unconfigured"

- If the status is "Passthru", then click on settings for that drive and change it to "Unconfigured"

- Confirm the settings .

- Then click on "Background Activities"

- Click on the Start button next to the Rebuild.

- Select the Source drive and the Target drive and Start the process.

- It will take 3-4 hours to complete the process and you can see the progress in the same page.


If you still have questions , please contact Promise Tech Support at 408-228-1500 or open an new case at htts:// 


Remo Kobler posted this 19 December 2016

Hello -

I have redone my entire drive per the instructions above, but still I have the SAME ISSUE that I had before I went through the process of buying a new HD for my Pegasus 2 per Promise's instructions???!!!!

The drive is successfully mounted, I have completed the rebuild "successfully"... but, I am still at phase 1 of my entire issue???? Which is UNABLE to write to my Pegasus 2.

My Mac running Seirra 10.2.1  sees the drive which I did an erase and ensured that it was formatted to "Mac OS Extended (Journaled) - BUT, when I restart the computer it immediately changes the drive back to MAC OS Extended - without "Journal" on the end?????

I have been dealing with this issue since December 1! Promise told me that my firmware/utility is up to date, but my drive 1 was failing, I spent the money and replaced it. Rebuilt it! And, still it is not working. I cannot write to the drive at all!???????

What are the steps to ensure that my MAC OS Seirra will see and WRITE to my HD as, it did before????? I upgraded to Seirra???

Please help me fix this issue!

kunal gohil posted this 01 October 2017

Hi Remo,

I am facing with the similar issue of not recognized Pegasus 2 R4 after a shut down through promise utility were you able to fix this problem.

Since Promise technical team is asking me to get in touch with third party vendor even after my product is under warranty.

Following is the reply from promise:

Customer informed the Pegasus volume is not getting mounted on the mac -He informed yesterday he shutdown the unit and moved the unit connected to the mac since then the volume is not getting mounted -He updated the firmware version of the unit as suggested by the support team and still the same issue -Checked the report no issues found with the unit or with the drive -In the disk utility the Pegasus volume is not showing up and he is getting a pop up message volume is not readable by the mac -Informed the customer it looks a file system issue on the mac and informed to check with third party vendor

Regards Karthik