Drobo fan when Mac is powered off

My Drobo is connected to a mac mini via firewire 800.

I never turn the drobo off, or disconnect the firewire cable. I do however shutdown the mac mini.

With the mac mini shut down, the drobo fan spins as though the mini was still powered up…

What’s curious is that the drobo fan actually powers up from an off state, a minute or two after the mini has been shut down. It then runs for quite a while before switching itself off again…

Is this normal behavior? can it be addressed with a firmware update?

If you have the drobo plugged in, the drobo and the drives are getting enough electricity to generate heat. So the fans will run when it’s in standby mode with your mac Mini shut down.

It’s perfectly normal.

[quote=“Jennifer, post:2, topic:606”]It’s perfectly normal.
Yes and no. I posted a question some time ago asking what temperature threshold starts the fan and got no answer. My Drobo log shows the fan starts although all 4 drives are 35°C or below. The fan spins periodically even in a cool room with low power drives which burn only 1.1W in standby.

Don’t forget that the Drobo itself has its own (quite capable) processor which generates heat too and that the drives’ internal temperature sensors are not the only source of the temerature readings for Drobo.


OK, but the Drobo processor should be in sleep mode too.
Nevertheless it would be nice if an idle Drobo was totally silent, like any good behaved TV, amplifier or DVD player.
The fact that the fan is working only part time and at slow speed means that we are not far from that…
…but not yet there :-(.

Right but there is still electricity going to the drives and the drobo when in standby. And THAT causes heat to be generated. If you do not want that at all, then unplug the data cord and the power cord when you put into standby. Your fan will not run that way.

I too am having this “issue” with the Drobo fans going on and off even when all drives have spun down or it’s in standby. The Drobo not being the quietest thing on earth makes this quite annoying since you can clearly hear it if the fan spins at anything but the lowest setting.

To me it seems overly sensitive since the drives are barley warm at all and even with the electricity going through the Drobo it should not need that much cooling. I mean come on, a box with four idle WD Green Caviar drives should not make more noise than a turned on iMac…

I’ll gladly trade some of my drives lifetime for silence :slight_smile:

Skulsson, do you expect your computer to stop all its fans just because the drive(s) has spun down? Drobo isn’t just some another “USB enclosure” - it’s essentially a specialized computer. It has its own mainboard filled with a CPU (with processing power available only to desktop machines just a few years ago), a memory: ROM and RAM - just like your computer has. It runs its own operating system which doesn’t halt just because the drives are off. All this has to be powered regardless of the drives’ state and generates heat when it’s running so don’t just look at the “standby current” figure in the drive’s datasheet and come to the conclusions based on that - it’s just pointless. There are lots of things going on inside this black box even when it seems to you that it just sits there doing nothing. Technically Drobo’s a computer - not a 4-drive USB enclosure with some USB-to-SATA bridge chip.

@skulsson Since you are putting the drobo into standby mode, go ahead and unplug the power after unplugging your data cable. Then you won’t hear the fan.

Honestly, if you are putting your Drobo into standby mode. you should then be unplugging the data cable then power.
You use standby to turn off your drobo.

Of course I know it’s more than a box (and a great product I like in many ways). But it’s still very annoying that it can’t make up it’s mind about the fan speed. And if it needs such hefty cooling even while the drives are spun down and it should be doing just about nothing it’s just poor design or/and components.

I also have a Mac mini running as a media center and it dead quiet while it plays HD movies, even with it’s fans running you can’t hear it. The Eee Box I had earlier was completly silent unless you put your head against it. Why should a Drobo in standby be worse?

I have no issues with noise from the harddrives or the fan kicking in while it’s working. Even if it would be nice to have a less steep increase in fan speed so it’s not either quiet or noisy but maybe somewhere in between. :)[hr]

I do, but having to unplug cables every night is not very handy and does not really fit the image of the Drobo being a slick and user friendly device. And if I leave my computer on over night doing something I do not want to unmount and unplug the Drobo.

EDIT: What I’m trying to say is that the noise to what-it’s-doing ratio just doesn’t add upp for me.

To your point of why Drobo in standby generates more noise than Mac mini or Eee…

Part of it is that there isn’t as much stuff insulating the sound, the other part is that the Drobo uses desktop 3.5-inch drives. Desktop drives generate more heat compared to laptop drives, and there are multiple of them in Drobo.

Same goes for stuff with less logic than Drobo. When you get into multi-drive external cases, they need fans or they kill the drives.

I’m curious as to where your Drobo is placed, especially what kind of surface it’s on. My Drobo is on an open metal shelf, my Tivo HD is above it, and I can hear the Tivo’s hard drive louder than the Drobo’s fan. If there’s a back wall near wherever your Drobo is sitting, it’ll bounce the sound of the fan back forward.