R8 Raid 6 with Partition Map Not Supported on Mac

  • Last Post 29 October 2019
Edward Campbell posted this 26 October 2019

I have a Pegasus2 R8 that I changed from a Raid 5 to a Raid 6.  All data backed up and reloaded successfully.  All files visible and accessible after reload.  When mac OS 10.14.6 rebooted, error message "The disk you inserted was not readable by this computer." 

Checked on different mac and with different cables yields same error message.

Mac Disk Utility shows Partition Map Not Supported; S.M.A.R.T. status shows Not Supported.

Promise Utility operates normally.

I obviously did something wrong when I did the conversion to Raid 6.

Here's detail


Raid 5 with 8 drives; no spare.


Raid 6 with 7 drives; 1 spare.

Stripe size 64kb

Sector size 512 bytes

Read Ahead/Write Back

Codec Scheme Q+Q

Operational Status OK, Synchronizing

Format (I believe):  Mac OS Extended (Journaled)

I would appreciate any advice.  My data is safe, although it takes more than a day to reload.

Thank you,



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Edward Campbell posted this 29 October 2019


Thank you for the response.  I changed the RAID level manually using the Promise Utility.  

I continued to analyze the issues after posting my request above, and realized I had failed to initialize the new virtual drive.  So I deleted the files, initialized the entire new virtual drive, and reloaded the files again.  Everything is now working perfectly.

Thanks again.  This case is closed.

Raghuraman Kannan posted this 29 October 2019

Hi Ed,

Please let us know how the RAID Level was changed. Was it changed via Migration or via Promise Utility.

Please register your email address and your Product  @ https://support.promsie.com and open a Web Case for further asssitance. We will take it forward from there.

Thanks !