Drobo S - Long Duration Drive Clicking-Tapping Access with Activity Light OFF ?

When I turned on my “Drobo S” today (after first turning on my pc that the Drobo S is connected to), shortly after the Drobo finished booting up (all bay lights green), I heard the drives in my Drobo "Clicking away/tapping away (a “Seeking like” sound, same sound as when I copy data to the Drobo; like the drives are being accessed) for about 5 minutes. During this long drive clicking period, the Drobo Activity Light remained Dark (off).

… I also have the Windows XP Indexing Service “OFF” (un-checked) for this drive.

… So, what is causing this drive clicking activity ???
… Is this normal ??? (and is it safe to write data to and copy data from the Drobo when its drives are making this long clicking activity for 5+ minutes )???

That’s not unusual. Drobo does some internal housekeeping when it starts up - not sure exactly what it is, but it’s likely an integrity check at least.

The activity LED doesn’t light because it shows external communication activity, not internal stuff Drobo itself is doing.


… So, is it safe to “Copy Data To” and “Copy Data From” the Drobo S, during this period when it is doing this “housekeeping” drive activity ???

P.S. BTW, last night I copied 35 GB to the Drobo S, before shutting it down. It was this morning, when I turned on the Drobo that it did its Housekeeping for 5 minutes. So, I was wondering is the long housekeeping duration, proportionally related to how much data was recently copied/written to the Drobo S ???

Sure, it’s completely safe to access Drobo while it’s “doing stuff” - if anything, you’ll just slow down whatever Drobo is doing.

As noted in other threads, Drobo is quite dynamic and intelligent about how it stores your data. It can change how how it stores data (simple mirroring, parity, etc) things based on the drive configuration and amount of free space.

As for whether its housekeeping is related to the amount of data, I really can’t say. It does seem to make sense.

Just curious, are you actually shutting down and powering off Drobo, rebooting it every morning?
Normally when you sleep/hibernate the attached computer, Drobo will go into “standby” mode, using minimal power and spinning down the drives.

IMHO leaving it on but in standby is less stress on the Drobo and drives compared to doing a full power-up cycle every day. The only time I actually power-down my Drobos is when I’m not going to use it for an extended period, like if I’m traveling. Though I often still leave it on since I end up accessing it while on the road, heh.


Thanks, for you help !

… Actually, yes. I guess I just don’t like the fact that when the Drobo S is in StandBy and the drives have spun down, it will still periodically cycle on and off the Fan.
… Its just not being very “green” to me to have the fan come ON in Standby Mode when the drives have spun down and the unit is in standby mode.



  1. My PC, when in Standby does not turn On a fan, for its internal hard drives ! … So, then why should the Drobo turn ON (cycle on/off) its Fan when in StandBy Mode ? (Why not needed by the PC, for StandBy of its internal hard drives, but yet needed for Drobo when in StandBy ?)

In the case of Drobo, the fan is temperature-controlled, so if it gets too warm, it’ll cool off. The Drobo electronics are still at least partially online, waiting for connection.

Depending on what mode your PC uses for standby, it could also do the same, though modern PCs and OSes use S3 (STR) for standby, so the CPU powers down and the fans power down too. The PSU still provides standby voltage, so it’s partially powered.

If the environment is cool enough, Drobo shouldn’t need to run the fans, but as long as electronics are powered, they will generate some amount of heat.


One last question:

When the Drobo is doing its Internal - “HouseKeeping” (seek activity on the drives), if during this period of Housekeeping, I start my length Backup/copy process to the Drobo, will the Drobo suspend its Housekeeping so that my Backup/Copy process is not slowed down in terms of Mbps thru-put and its completion time ???

— OR —

Will the Drobo continue with its Housekeeping while my Backup/Copy process is wiiting to the Drobo and effectively effect my completion time by making my Backup process take longer with a reduced Mbps data thru-put ?

If you start writing to the drobo, the internal housekeeping will stop.


Thats great ! Just how I was hoping Drobo S would work.

P.S. Curious as to what kinds of things is Drobo S actually doing, during its Housekeeping Periods of 5 mins in length (following Powering On the Drobo or coming back up from Drobo’s StandBy mode that I noticed recently on my Drobo S ?

Thanks !

[quote=“JosephB, post:5, topic:1645”]

  1. My PC, when in Standby does not turn On a fan, for its internal hard drives ! … So, then why should the Drobo turn ON (cycle on/off) its Fan when in StandBy Mode ?[/quote]
    You are kind of assuming that the disks are the main power consumption.
    But when idle they are not : according to Drobo-S specifications, Drobo-S idle power is 12W, while 5 “green” 2TB drives use only 4W (5x0.8W).
    So the Drobo internal electronics has 3 times the disks idle power consumption, which explains the fan on/off behavior even when idle.

I have the same behavior on my Drobo-V2, for the same reason, although Drobo-V2 idle power is 5W compared to Drobo-S 12W, and it highly irritates me.
Actually, I initially intended to replace my Drobo-V2 by a Drobo-S, until I realized that twice as much idle power meant twice as much fan noise when idle :frowning: .

This is actually poor hardware design by Data Robotics, who decided to economize the few additional electronics components which would reduce their mainboard idle consumption to 1 W or below. Let us hope for a Drobo-V3…