I ran it from the unRAID server. Here are my steps.
Follow these steps at your own risk!
The steps I followed, yours steps may vary.
Restored backup files from /boot/v6.0-beta12/
Reboot
UI should show beta12 as the version when it's done restarting.
Make sure your array is shut down.
connect via ssh or login to the machine directly
mkdir /boot/testdisk
cd /boot/testdisk
wget http://www.cgsecurity.org/testdisk-7.0-WIP.linux26-x86_64.tar.bz2
tar -Bxvf testdisk-7.0-WIP.linux26-x86_64.tar.bz2
cd testdisk-7.0-WIP
./testdisk_static
Write log
Figure out which disk you need to fix by looking at the Web UI and determine which cache /dev/sd? is blue.
This was changing between reboots for me, so make sure to check the UI before selecting the drive.
Intel -> Analyse -> Quick Search -> Use arrows to set type (I chose logical first to match what the other drive had, but that didn't work after a reboot) I ended up selecting P for primary, and that worked for me. Yours may be differt. -> Continue -> Choose Write
Exit program, and reboot from the UI.
When it came back up my cache drives were both green, so I started the array and everything came up as expected. All my Dockers are working as they were before the beta13 upgrade.
If the drives aren't green in the UI, repeat the steps within the ./testdisk_static program and try another partition type option.
-Eric/Heuristic