My Drobo v2 is filled with 4 2TB Hitachi 7200rpm. When I changed out a drive from a 1.5TB a few weeks ago, I was hearing the fan running most of the time during the 72+ process of relayout and I started giving it more thought.
Although the room with the Drobo isn’t very hot, I have, in general, noticed that the fans run off and on with this Drobo, and I have thought maybe the fan shouldn’t run so much but wasn’t super concerned. During a re-layout, the drives run for 3 days or more ( I have 3.5TB of data on the Drobo). This turned out to be a good opportunity to identify how hot the drives are getting. So, being aware of the some of the suggestions here that 5400/5900 rpm drives perform equally as well in the Drobo, i thought about changing out to a lower rpm drive in order to see the effects.
Big difference so far in observed heat. I replaced the bottom 2TB 7200rpm with a 2TB 5900rpm. The relayout is going on for 48 hours so far. The 7200rpm ares burning up. I can only keep my hand against any of them for a few seconds.
But, the 5900rpm is very warm but I could keep my hand against it comfortably.
If there is truly no advantage to 7200rpm versus 5900rpm in the Drobo v2, due to CPU design, then I am strongly considering changing out the lot and re-using the 7200rpm somewhere else.
What speed drives do you have?