I have the exact same configuration on my Drobo Mini and have successfully been running TM backups for well over a year via Thunderbolt cable.
However, I have a Mid 2011 iMac 27" and today swapped out the HDD for an SSD. Everything worked perfectly until I tried to run the Mac recovery sequence.
The Drobo Mini was not recognized as a “Time Machine” backup drive. I opened the Disk Utility and could see a drive mounted with some generic name and a single partition, but that was about it.
Nothing I did would let me proceed with the recovery.
I called the support line and the process discussed was something like:
- Shut everything down
- Unplug the power from DM
- Replace TB cable with USB3.0 cable (even though my iMac only supports 2.0)
- Remove all the drives from the DM
- Boot and get the system to pick-up the DM
- Shut everything down again
- Put drives back in
- Should be picked up
I did not follow these instructions as removing my drives from the DM rebooting, replacing, etc. seemed a bit drastic and I wasn’t entirely sure whether my files would be safe having removed and replaced them… I couldn’t get any reassurances so…
I ended up doing an Internet Restore of Lion, then upgrade to El Capitan. I used an external cable to hook up my old HDD and have been manually moving files over.
So my question to the community is: WTF did I miss? The proposed solution seems very risky and a bit of a hack yet I’m left with the situation where the Drobo Mini works flawlessly as a TM backup yet I am unable to use it as a restore device and that completely defeats the point of doing a backup in the first place?!?