I have five 2 TB Hard-Drives installed in my Drobo S. It’s connected via Firewire 400 to my Mac Pro under Mac OS 10.6.7.
The harddrives are making a constant clicking noises (like they do when powering up or shutting down) when i use the Drobo S. Drobo Dashboard says everything is OK.
Please tell me that this isn’t normal behaviour, because this clicking noises are driving me mad. Also, i think that these noises just begun currently and not from the beginning.
Any idea what causes these noises?
are they western digital?
some of the WD hard drives have a “feature” where they unload the heads from the platters after 7 (or is it 8?) seconds - this reduces both wear and power consumption… but then when you need data obviously the head move back onto the platter
this si a great idea for a desktop scenario - but in some RAID arrays (and when using linux) the access patterns tend to mean that read/writes may only occur every 10 seconds or so - so the heads are essentially constantly loading and unloading (which would explain your clicking)
let me know if your drives are WD-GP
Nope, i have 5 x Seagate ST32000542AS LP installed in the Drobo.
damn, that was my only idea then 
i avoid seagates like the plague - the only time i ever lost data was seagate’s fault!
but generally clicking is not a good noise to be coming from a hard disk.
turn your drobo s off and remove the disk you think is clicking (or a random one if they are all doing it) and connect it directly to a computer and run seatools on it - see if it passes
In general, not realated to Drobo, usually clicking sounds mean that the HD is about to die, from my experience anyway.
WD Idle3 timer defaults to 8 seconds. But I agree with OrangeCoffeeMug, constant clicking/ticking on an idle drive is the sound of impending drive death. Not sure about Seagate, but WD lists ones of the RMA reasons as “Drive clicking” 