When Your Drobo Won’t Mount

Posted by mrmyth on March 21, 2009
Computer Tips

For a few months, the two gadgets of my desire has been the Drobo and the Fujitsu Scansnap. This article is about my recent experience with the Drobo. The Drobo is a wonderful thing that you can hook to your computer, throw any old Serial ATA hard drives into, and back up Terabytes worth of data (up to 16TB) easily and without worries. They have touted this thing on TWIT and Macbreak Weekly and I’m sure in many many other places. It is the wonder box, because it stripes the hard drives so that your data is backed up in a what they call a “BeyondRAID” configuration and even if a hard drive dies or you pull one of the hard drives out and put another one in, you won’t lose anything.

It’s also super simple because you can just look at the lights on the front to see how the drives are doing and the blue lights on the bottom show how much storage you have left. What could be simpler?

DroboHaving never seen one of these in person, I was interested when I saw one of my clients had gotten two and had them working away.

The first thing I noticed was that one of the Drobos was not mounting on the iMac to which it was connected. The Drobo comes with some software that runs on the Mac and gives you information about what is going on with the device. This “Drobo Dashboard” was saying that the disk was “unlabeled.” It used to have a name, but now it had none. In the Dashboard there is a pie chart that shows how much space is used and how much is available. I could see there was 750 Gigabytes worth of data on this thing, that was now unreachable. I checked the disk utility and the Drobo was showing up but you couldn’t verify the disk, repair disk permissions or repair the disk.

What I found was that this particular Drobo had a habit of spontaneously disconnecting from the iMac. Why? Well after a little investigation I found that the firewire 800 cable had a broken interface. The little square in the plug that went to the Drobo was broken. This must have caused it to dismount on its own repeatedly without being ejected. The warning that comes up when you unplug a drive from a Mac, might have some truth to it. For the same reason we don’t make a habit of shutting our computers down with the power button, we don’t disconnect drives without ejecting them. What can happen, especially, apparently, with the Drobo, is that after a while the drive structure can become corrupted and all of a sudden the computer doesn’t know what is on the drive anymore. The data is there, but the file structure is not.

I called Drobo support and talked with a very nice woman, who walked me through the process of updating the dashboard software and the Drobo firmware. In the end the disk was still unlabeled and she suggested that I try a third-party software like Disk Warrior, Data Rescue II or Techtool. I took the firewire off and replaced it with USB and ran Disk Warrior on the Drobo and after it went through and found the directory structure was damaged, it mounted the drive on the desktop and recommended that I just try to recover the data. It said it couldn’t replace the directory structure.

I then decided to copy the data to another drive and let it run overnight. The copy message said it would take 33 hours. The copying stopped on its own long before the data was copied over. I came in the next morning and decided I was going to try a command line utility that was suggested to me to repair the file structure. Before doing that I decided to just plug the Drobo in with a different firewire cable and reboot the computer. The Drobo mounted and seems to be fine.

What probably happened: The Drobo had a bad firewire cable that caused it to unmount unexpectedly. Eventually the file structure became corrupted. Either Disk Warrior or the Apple operating system rebuilt it.

So here’s what I learned from this experience.

1. Make sure your firewire 800 cable doesn’t have a broken little square in the end. This will cause disconnections that can corrupt file structure and leave your Drobo “unlabeled.”

2. Drobos aren’t infallible. I think they are mainly just a great place to back stuff up.

3. With these larger hard drive spaces, moving data is going to become more an more difficult. It takes a long time to move 750 GBs of data. If there is any error along the way it just stops. Applications such as Chronosync, make this much easier to synchronize and copy data. Once the Drobo was up and running I copied the data to another drive using Chronosync.

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3 Comments to When Your Drobo Won’t Mount

  • Shawn Landry says:

    This is the solution to my problem which I had with Drobo which is similar in nature, but not exactly the same (with drive not mounting). I currently have a trouble ticket open with Drobo Inc. and here was my last post with them and how I rectified my issue.

    “Although I did try some of the tools that were recommended, non of them were able to recognize the Drobo properly. I did, however, find another tool that was able to see the drive and its current file structure. The tool is called TestDisk 6.13 (<a href="http://www.cgsecurity.org/wiki/TestDisk_Download&quot;), which is an open source program for all variants of Operating Systems. TestDisk is an application that runs within a Terminal window, so it is not quite user-friendly; however, I was able to re-establish a full mount of the Drobo Disk…At least to a point where I could run Disk Warrior and rebuild the drive, which I completed successfully.

    The steps I took to reestablish a connection with my Drobo are as follows: (This tool should only be used if no other tools such as Disk Warrior and Tech Tool Pro can see the drive AND the drive does not mount)

    1. Run the TestDisk application from the folder you unzipped it into.

    2. Choose [No Log] unless you require a log file.

    3. Choose [disk1] and [Proceed] — Warning — [disk1] is what I chose as it was the only externally connected hard drive I had (with 17TB labelled).

    4. Choose [Intel], even though the Mac uses partitions that are formatted as HFI+ Drobo Inc. uses FDISK to partition its Master Boot Record and EFI.

    5. Choose [MBR Code] – To recreate the Master Boot Record.

    6. Type "Y" for yes to accept that you are modifying the Master Boot Record.

    7. Type "Y" again to verify the change.

    For the symptoms I mentioned in previous post (**see below), almost immediately the Drobo mounted on the desktop with what appeared to be the correct file structure. I ran Disk Warrior and it finally recognized the drive. I rebuilt the structure of the drive just to be safe, and I found it did have many errors on it, which were then corrected.

    I then began the vigorous task of ensuring the data on the drive was still working, and I did find a few files that were corrupt, but nothing too major.

    Although I was able to rebuild most of the data on the Drobo, the issue that corrupted the Master Boot Record in the first place is still at large. All I did was try to replace one bad drive, and dual disk redundancy was enabled as well, so it should have had no problem. Because the Master Boot Record is so vital to the BeyondRAID filing system, a tool should be added to the Drobo Dashboard which allows the user in such a case as mine to rebuild this sector in the event of catastrophic data failure. It does no harm to the system even if the customer does this with no real purpose. The Drobo should also be monitoring this sector on its own to ensure its structure is always intact by keeping a copy of the MBR data on different drives in Drobo/in EEPROM/and on the customers system within the Drobo Dashboard App. For this reason I keep this trouble ticket open."

    Keep in mind, Drobo Inc. labeled this problem as "solved" under the trouble ticket even though it isn't. I hope this helps you out, it took hours of learning about their filesystem (sarcastic grin) to finally figure it out.

    **Symptoms I had:
    -Drobo drive would not mount; yet,
    -Drobo Dashboard reported drive as healthy
    -Disk utility would not verify or repair
    -Disk Warrior and TechTool Pro do not recognize connected drive

  • Shawn Landry says:

    This is the solution to my problem which I had with Drobo which is similar in nature, but not exactly the same (with drive not mounting). I currently have a trouble ticket open with Drobo Inc. and here was my last post with them and how I rectified my issue.

    “Although I did try some of the tools that were recommended, non of them were able to recognize the Drobo properly. I did, however, find another tool that was able to see the drive and its current file structure. The tool is called TestDisk 6.13 <a href="http://www.cgsecurity.org/wiki/TestDisk_Download&quot;, which is an open source program for all variants of Operating Systems. TestDisk is an application that runs within a Terminal window, so it is not quite user-friendly; however, I was able to re-establish a full mount of the Drobo Disk…At least to a point where I could run Disk Warrior and rebuild the drive, which I completed successfully.

    The steps I took to reestablish a connection with my Drobo are as follows: (This tool should only be used if no other tools such as Disk Warrior and Tech Tool Pro can see the drive AND the drive does not mount)

    1. Run the TestDisk application from the folder you unzipped it into.

    2. Choose [No Log] unless you require a log file.

    3. Choose [disk1] and [Proceed] — Warning — [disk1] is what I chose as it was the only externally connected hard drive I had (with 17TB labelled).

    4. Choose [Intel], even though the Mac uses partitions that are formatted as HFI+ Drobo Inc. uses FDISK to partition its Master Boot Record and EFI.

    5. Choose [MBR Code] – To recreate the Master Boot Record.

    6. Type "Y" for yes to accept that you are modifying the Master Boot Record.

    7. Type "Y" again to verify the change.

    For the symptoms I mentioned in previous post (**see below), almost immediately the Drobo mounted on the desktop with what appeared to be the correct file structure. I ran Disk Warrior and it finally recognized the drive. I rebuilt the structure of the drive just to be safe, and I found it did have many errors on it, which were then corrected.

    I then began the vigorous task of ensuring the data on the drive was still working, and I did find a few files that were corrupt, but nothing too major.

    Although I was able to rebuild most of the data on the Drobo, the issue that corrupted the Master Boot Record in the first place is still at large. All I did was try to replace one bad drive, and dual disk redundancy was enabled as well, so it should have had no problem. Because the Master Boot Record is so vital to the BeyondRAID filing system, a tool should be added to the Drobo Dashboard which allows the user in such a case as mine to rebuild this sector in the event of catastrophic data failure. It does no harm to the system even if the customer does this with no real purpose. The Drobo should also be monitoring this sector on its own to ensure its structure is always intact by keeping a copy of the MBR data on different drives in Drobo/in EEPROM/and on the customers system within the Drobo Dashboard App. For this reason I keep this trouble ticket open."

    Keep in mind, Drobo Inc. labeled this problem as "solved" under the trouble ticket even though it isn't. I hope this helps you out, it took hours of learning about their filesystem (sarcastic grin) to finally figure it out.

    **Symptoms I had:
    -Drobo drive would not mount; yet,
    -Drobo Dashboard reported drive as healthy
    -Disk utility would not verify or repair
    -Disk Warrior and TechTool Pro do not recognize connected drive

  • Michael says:

    Shawn you saved the day! My drobo is fixed. Thank you!

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