Drobo time machine volume unmounts -

Hello -

I have an original 4-bay Drobo (each bay with 3TB drives) - firmware 1.4.2 and dashboard 2.4.3 - on a Mac running OS 10.8.3. The Drobo has two volumes: one used for storage, another for Time Machine backups. I’ve had this Drobo since release, with many HD upgrades with minimal problems in the past.

Recently, I needed to reinstall my Mac OS for an unrelated problem. Following that, I was having a problem where Tie Machine was not backing up to the Drobo volume - Console messages were reporting the TM volume was unmounting. I seemed to be able to solve this problem by changing my Energy preferences to prevent HD from sleeping when possible.

However, it seems like randomly, I’ll notice my Drobo time machine volume spontaneously unmounts - I’ve actually seen it disappear off the desktop - while the other storage volume remains. Of course, when this occurs, time machine no longer backs up (looking for volume). I can remount the TM volume using Disk Utility - there are no errors or problems reported in dashboard. Console is still reporting: “Stopping backup to allow backup destination disk to be unmounted or ejected.”

Any thoughts why the Drobo time machine keeps unmounting? Thanks -[hr]
Forgot to mention, my Drobo is connected by firewire

The first thing I’d try is connecting via USB. I know, I know, Firewire gets the finger pointed at it all the time but seriously, it’s one of those things that works great if it works for you, as it does in my case. But for a number of others, they have trouble, sometimes odd trouble.

USB is a much better-defined and common interface, hence it gets more testing and attention.

It’s kind of like how PAL DVDs with only MPEG audio track(s) are legal per DVD spec. NTSC DVDs with only MPEG audio track(s) are not legal per DVD spec, so virtually all commercially-produced discs contain either an AC3 track or a PCM track. Thus, guess what rarely gets tested by DVD player manufacturers? :slight_smile:

Thanks -

I’ll give the USB a try.

I’ve used the FW800 connection since purchasing the Drobo so it’s weird that it would become a problem all of a sudden. The USB transfer speed hit will be unfortunate.

I’ll report back when I see what Time Machine does with the Drobo connected by USB.

Best -

As the speed limiter on a 4-bay Drobo is really the Drobo processing, the difference between USB and Firewire should be negligible, unless you have a busy USB bus or your Firewire has a less-clogged path on the motherboard.

It is odd if Firewire has been working all this time, but sometimes things just go haywire out of nowhere… That stupid “flip” from good to bad. Had that with a charger recently - was working fine, running fine, then all of a sudden the light went off and it refused to work again.

I had a Drobo v2 that ran flawlessly for two years on my Late2009 iMac via FW800.

It ran perfectly on my new Mac Mini Server…until I installed 10.8.3. Then it was kernel panic every 6 hours. I moved it to USB and it’s been rock-solid.

I only use this Drobo for Time Machine, so the performance hit from FW to USB wasn’t noticeable to me.

Unfortunately, I’m having the same error with USB:

Apr 25 05:39:12 Dads-Intel-Xeon-Mac.local com.apple.backupd[37705]: 6.47 GB required (including padding), 798.6 GB available
Apr 25 06:01:20 Dads-Intel-Xeon-Mac.local com.apple.backupd[37705]: Stopping backup to allow backup destination disk to be unmounted or ejected.
Apr 25 06:01:21 Dads-Intel-Xeon-Mac.local com.apple.backupd[37705]: Copied 10696 files (3.96 GB) from volume MacPro 1.
Apr 25 06:01:30 Dads-Intel-Xeon-Mac.local com.apple.backupd[37705]: Cancellation timed out - exiting

Also ran Disk Warrior on the Drobo volume before trying USB.

Any other thoughts??? Thanks -

I think it’s time to generate a logfile and send it to Drobo. They can tell you what (if anything) the Drobo is seeing when the disconnects occur.

hi bruckner, do you know if any type of scanning/indexing tools were made active (eg after you reinstalled the mac os) which were “not” active before?

i remember when i had a volume shadow service running in the background in windows ages ago, which was causing conflicts with windows drobo and it kind of unmounted (eg vanished from my computer).
the basic fix was to not keep that service running all the time, and now i just enable it when i need it, and dont believe i’ve had the problem for ages :slight_smile:

You may be onto something here, Paul -

My mac has a disk utility program by Micromat called Checkmate - runs HD checks while the mac is idle. Haven’t found it terribly useful, but it hasn’t been in the way before - as best as I could tell.

Decided to uninstall Checkmate after your comment and time machine seems to be backing up to my Drobo without the unmount errors for the last day or so, so we’ll see.

I’ve had Checkmate installed with OS 10.8.3 and my Drobo before without this problem, just after the recent OS reinstall maybe something’s not quite right…

We’ll see what happens after a few days.

Thanks for the suggestion!


ok cool keep us posted bruckner,

(also check about a way to disable that checker program, sometimes programs have a way to do that instead of uninstalling, especially if you want to keep using that program, but yes also uninstalling can remove any “hooks” into the system which could cause conflicts or “locking” features)

if you can, try to repeat the same backups/tests over the next few days a couple of times etc to see and hopefully it will work out for you… if not, then:
“to the batmobile!!”… :slight_smile: