Pegasus2 R8 + Mac Problems

  • Last Post 31 December 2023
Kieran Walsh posted this 29 December 2023

Mac owner using a Promise Technology 32TB Pegasus2 R8 Thunderbolt 2 RAID Storage Array (7200 rpm). Since 2015 it has worked flawlessly.

I'm currently using a 2023 Mac mini. M2, 24GB memory, OS 13.3.

Today I noticed the Promise was painfully slow... investigated further and it started giving me "Bad Sector found on physical disk" alerts and the external light on one drive turned amber. It would still show up in my Finder but if I selected the Promise I would just get the beach ball of death.

I decided to plug it into my old iMac and the Promise seems just fine there. Using the Promise utility it confirms that there was a bad sector on one of the disks, but I can still use it as normal, and all the external lights are blue (normal). I'm currently backing up the really important files.

Why do you think that it seems fine with my old Mac? Do I have to go through the hassle of replacing that one drive or is there something I can do to my Mac mini? If I need to replace the drive will any 4TB/7200 rpm drive do?  For instance:


Thoughts appreciated. Thanks.

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Babatunde Akinkuolie posted this 30 December 2023

Hello Kieran,

 When a drive accumulates numerous bad sector errors, it's advisable to replace it promptly. As the Pegasus2 is already End-of-Life (EOL), a replacement drive will need to be sourced from a third-party vendor. You can purchase any drive model/brand of the same size by referencing the Hard Drive Compatibility list tested with the Pegasus2. Most other drives should work as well. Please refer to this link for the compatibility list:


Once you've obtained the replacement drive, follow the instructions provided at  to rebuild the disk array.

Kieran Walsh posted this 30 December 2023

Thanks so much for your response.  Unfortunately it looks like none of the drives in the compatibility list are manufactured anymore.  Do you think this would will do:

Babatunde Akinkuolie posted this 31 December 2023

 Hello Kieran,

While the drive you've chosen wasn't specifically tested, there shouldn't be any issues with its normal functionality in your Pegasus unit. You can purchase any drive model/brand of the same size, and it should operate smoothly. It's recommended to ensure the replacement drive matches at least the same spindle speed as your existing drives (usually 7200rpm).

Additionally, it's important to confirm that your unit is running the latest firmware. You can find guidance tailored to your Pegasus Model (Pegasus 2) in this link: