Archiving to Blu Ray using .dmg: Errors abound

Hi:

I'm trying to archive my event and project files from a FCPX video I just completed. I've deleted render files, gotten rid of the optimized media, and all I have is the project folder and the event folder, plus the final exports/shares of the project.

I wanted to try out using .dmgs this time to keep it all in one shell, so to speak. I tried using Toast Titanium to burn all this to blu-ray disks as data. It failed 4 times. Can't remember what the error was, but I just kept trying again. Finally, I ditched the .dmg burn idea through Toast, and simply put the folders from the project/event into Toast (without the .dmg packaging). Still, I got a fail twice. This time I remembered what the error was: "The connection is not stable." Not sure what that means. My burner is external and the connections seem fine to me. Anyway, if anyone knows why this all won't work, I'd love to get some insight. For now, I have a .dmg on my desktop!

By the way, would you burn the disk image's mounted drive's contents using Toast or would you burn the .dmg file itself (the little icon with the white square background and the disk drive image in the foreground)?

Another important piece of info is the .dmg is 134GB so it's gigantic. Would take 6 BDRs.

For now, I'm just copying the .dmg onto an older USB3 external drive. I'd love to archive on BDR for extra backup but this will do for now.