Time Machine Encrypted Backup Disappeared

This is not a critical issue for me, but I wanted to post it in the event other folks experienced a similar issue. Thankfully I have Time Machine backup of my iMac on both my Drobo 5N and single external hard drive.

End of last week I noticed that for some reason my Drobo 5N encrypted Time Machine backups were failing. Not sure why this was, as since I bought it I have had no issues. I checked my Drobo Dashboard and while my Time Machine share was still present it was completely empty and my total available space was what it would be if I didn’t have any data backed up at all. I went into the share itself and noticed the encrypted .dmg file was only 1KB …

No idea if this was a Drobo thing, a Mac OSX thing, or something w/ the Time Machine backup because it was encrypted? Haven’t done much research to see if others have had this problem, if this is a known issue, or just a one-time fluke.

Again, for me this backup wasn’t crucial as I have a duplicate, but as I reset up my Drobo 5N Time Machine backup I’m now a bit concerned about reliability.

Drobo 5N - 3.2.1 firmware (now on 3.2.2); 5 x 3TB Western Digital Reds w/ 128GB mSATA.
Drobo Dashboard - 2.6.6 (now 2.6.7)
iMac - OSX 10.10.3 w/ encrypted Time Machine Backups

Unless the situation has changed very recently, encryption of Time Machine backups isn’t supported. It’s a “Drobo thing”. Trying to use compression can trash your Drobo volume, a fact I find less than impressive.