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Mac Studio and SoftRAID 6 compatibility

I have been waiting for years for Apple to come out with a truly powerful mid-range computer for photographers and video editors. The new Mac Studio fits that description well. I purchased on to replace my aging iMac and overall I am very impressed with the computer. However…

After I used Migration Assistant to migrate all of my files and applications from my iMac to my new Mac Studio, the new computer rebooted and immediately blue-screened and crashed. I tried booting again with the same result. I wondered if there was a problem with the external drive and RAID software, so I unplugged the RAID enclosures from the Thunderbolt port on my Mac Studio and booted again. The computer booted up without any problems. I reinstalled the SoftRAID software, and rebooted again. After the boot, I plugged in my Thunderbolt drive enclosures and they fired up and SoftRAID recognized them without any issues. I was able to access all my files.

In two weeks of use, however, I noticed that I would occasionally return to my computer and find that it had crashed and rebooted. I examined the crash logs and it seemed to be an problem with the MacOS system playing well with the SoftRAID driver. Restarting it successfully required the same routine of unplugging the RAID enclosures and booting and then plugging them into the Mac Studio only after a successful restart.

I contacted SoftRAID support, and they responded with the following:

There is a M1 bug that affects a small but significant number (5% perhaps) of users. The system will kernel panic when connecting the volume, or shortly thereafter. It’s some kind of threading issue, we are waiting for Apple to fix. But we discovered two main workarounds if you suffer from this: Disconnect one disk when connecting the volume, then push it back in after 5 minutes or so. Or create a new RAID 5 volume with 64K stripe unit size.

And indeed, their FAQ page has this problem problem at the top of the list.

Fixing the issue

I keep my large multi-terabyte photo files on a set of external OWC Thunderbay 4-disk boxes. I use SoftRAID to configure these enclosures in a RAID-5 configuration, which allows the loss of one disk in the array without any data loss. I keep two of these enclosures running. One is my primary working disk for all of my photo library, and the second is a cloned version of the same library of files, but I only clone it every week, reasoning that if I make some gigantic screwup on my main volume, I have a week to resolve the problem before any problems get cloned to my other enclosure.

My plan was to first back up my primary working data volume onto a single high capacity disk as an insurance policy. I do this routinely and even keep one of these disks in a safe deposit box as insurance against complete destruction of my house! I then opened the SoftRAID application, and selected the volume I plan to recreate using a 64K stripe unit size. I right clicked and removed the safeguard and then right clicked again on that volume and deleted it:

Deleting the volume will destroy all the data on the RAID volume! Test your backup to make sure it is good before doing this step

Deleting a SoftRAID volume

The next step is to create a new volume. In the left panel, select the drives you just released from the previous RAID-5 volume. Note that there will be a notation on each drive that it is “not used for any volumes”.

Creating a new SoftRAID volume ‘Creating a new SoftRAID volume’)

Click the Create button, and a dialog box will pop up:

Set 64K Stripe size in SoftRAID create volume

The default stripe size is 16K. This selector button should be clicked and changed to the 64K strip size. Click OK and the new RAID volume is created.

The final step is to copy all the data from the backup disk onto the newly created RAID-5 volume with the 64K stripe size.

This should fix the issue.