1 Dead Drive after Mac Update Pegasus r4

  • Last Post 28 June 2021
Brian Jeong posted this 27 June 2021

 When updated the mac os to Big Sur, it suddenly detected a dead drive.

I am currently using raid 0 and lost access to the data.

I wanted to see how i can recover the data and make the drives work again.

Can i get a new harddrive and replace and rebuild? Would that recover all of my data?

Or did i just loose everything because it was raid 0?


Please help!


R P posted this 28 June 2021

Hi Brian,

You can't rebuild with a RAID 0.

It's hard to say what happened, but if they drive is OK you can force it online and that should bring the RAID online.

This can only be done from the terminal using promiseutil. If the dead drive was PD2, this would be the command. Open a terminal and type the following commands.

phydrv -a online -p 2

Substitute the correct drive number if it's not PD2.

RAID 0 is not recommended. If one drive dies than the LUN is offline. By default the Pegasus ships with RAID 5, which has 1 disk of redundancy. If possible it would be a good idea to copy the data off and create a RAID 5, the wizard is a quick and easy way to do this.