Pegasus R4i - using disks in an external device?

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Matthias Deneke posted this 28 November 2025

My MacPro 2019 is going to be sold soon and I was wondering if I could continue using the 4 disks of my Pegasus R4i (RAID 5) in an external device, connected to my new Mac Studio?

Thank you in advance. 

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Frank Bosma posted this 28 November 2025

Hi Matthias,

yes, you can install the 4 disks in any external Pegasus device, for instance the Pegasus32 R4, but they will also work fine in a 6 or even 8 bay unit.
The existing logical drive on your disks will mount as before.

It does need to be a Promise Pegasus device though due to our proprietary hardware RAID engine.
https://www.promise.com/Products/Pegasus/Pegasus32

Kind regards,
Frank

Matthias Deneke posted this 04 January 2026

Hi Frank,

thank you for your help. 

I live in Germany and all I can find are Pegasus devices with included drives. Can I somewhere buy e.g. a Pegasus32 R4 without drives?

Best,
Matthias

Frank Bosma posted this 06 January 2026

As far as I know Promise only sells new Pegasus devices with HDDs through distributors and resellers listed on the 'where to buy' page.
It is possible that certain resellers offer refurbished devices (if available of course) but I assume these also come with disks.
Best bet for empty chassis would be 2nd hand market place sites like ebay.
The disks will work in any model Pegasus but only the Pegasus3 and 32 models have the USB-C type Thunderbolt3 connection.
For older versions you will also need a Thunderbolt 2 > 3 adapter from Apple to connect it to new Mac host.

Earl Robicheaux posted this 30 June 2026

I have a similar Issue. Apple is going to discontinue support for the MacPro late 2019 with the intel chip. I have a Ri in it and am looking at buying a used, either 32 R4 or R6. My question is can the 4 diskk array in the Ri be moved to a R6 with two additional disks. My guess it cannot and that the only way to preserve the present array would be a R4.

R P posted this 30 June 2026

Hi Earl,

My question is can the 4 diskk array in the Ri be moved to a R6 with two additional disks.

Yes they can, the Volume should mount. Regarding the 2 additional disks, what do you want to do with them?

My guess it cannot and that the only way to preserve the present array would be a R4.

R4 is the last part of a Pegasus model name, it says only that it has 4 disks. The RAID set can be moved to any Pegasus model (1,2,3,32) with 4 or more slots and the Volume will mount as long as the filesystem is undamaged. 

Earl Robicheaux posted this 4 weeks ago

I'm sorry, I shoulld have done a better job of asking my question. In the Ri I have a RAID setup for my photography files. (it is backed up and a copy of one I have at another physical location) What I am wondering is can I remove the 4 disks from the Ri and install them in a 32 R4 and preserve the data in the RAID. It seems rather complicated as I would think I would have to put the drives in the same order in 32 R4 as they are in the Ri....I just had to purchase a new 32 R6 (60TB) and build a RAID 6 which took over 2 days before I was able to load data. I know this is not necessarily an easy task.

R P posted this 4 weeks ago

Hi Earl,

What I am wondering is can I remove the 4 disks from the Ri and install them in a 32 R4 and preserve the data in the RAID.

This question has been answered 3 times in this thread and once in response to you but you just won't take YES for an answer.

It seems rather complicated as I would think I would have to put the drives in the same order in 32 R4 as they are in the Ri....

You don't necessarily have to put them in the same order, but doing so is a piece of cake, the R4i slots are numbered, move the drive in the R4i #1 bay to the top slot in the Pegasus32, move the drive in the R4i #2 slot to slot 2 in the Pegasus32 (second from the top), etc...

Make sure the Pegasus32 is powered off when you insert the drives.

Then connect the Pegasus32 to your Mac and the Volume should mount.

It's so simple even a caveman could do it (apologies to any cavemen that might still be around).

Earl Robicheaux posted this 1 weeks ago

Sorry to be a pain un the neck. 

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