Jennifer, I am completely astounded by this advice, as it goes against everything that I have heard over the last 18 months!?! I don’t mean to shoot the messenger, but please cite chapter and verse of where you heard this, and from whom, as I frankly believe that you have been misinformed.
My understanding is that the Drobo has a built-in battery that is supposed to be sufficient to make sure that any pending write operations complete in the event of a sudden power loss.
However, if there happened to be a data transfer operation going on at the time that you suddenly jerked the data cable, there is a very good chance that a corrupted sector will result, or even worse, a corrupted directory.
Obviously, the best course is to shut down things gracefully, but without a graceful shutdown switch on the Drobo (V1, V2, or DroboPro), unlike competing units, we are dependent upon the Drobo Dashboard, and sometimes it doesn’t work, or isn’t available.
So my practice in this case has always been to pull the power cord first.
If this is an incorrect procedure, I would certainly like to have confirmation directly from one of the senior DRI engineers as to the exact reasoning behind the alternate strategy.