I know drobo is not yet officially supported on yosemite...
But, I updated the firmware to 3.1.1 and dashboard 2.6.2 on my 5D to then find it wouldn't connect via thunderbolt to my mac.
The fix is to just uninstall the dashboard which in turn removes DDService64d.
Then restore (or better reinstall) dashboard 2.5.3 which installs the older service.
this will then allow you to use your drobo via thunderbolt on yosemite beta.
You don't need to mess with the updated firmware on the drobo, it will be fine.
But, I updated the firmware to 3.1.1 and dashboard 2.6.2 on my 5D to then find it wouldn't connect via thunderbolt to my mac.
The fix is to just uninstall the dashboard which in turn removes DDService64d.
Then restore (or better reinstall) dashboard 2.5.3 which installs the older service.
this will then allow you to use your drobo via thunderbolt on yosemite beta.
You don't need to mess with the updated firmware on the drobo, it will be fine.