One week with the Drobo on Linux

16 March 2008 » Drobo, Linux, System administration

I’ve been in the market for a media storage and/or backup device for my home network for some time now.

I don’t have any more free bays in my server, so adding space there wasn’t an option. Reusing any of the spare machines cluttering up the basement didn’t make much sense either, from a power or capacity point of view.

I had considered a few consumer network attached storage devices, but nothing really felt right for my needs; an SSH interface for nightly rsync backups, relatively easy setup, and future expandability.

Fortunately, I bounced the idea off of my gadget-savvy co-worker Kashif. He pointed me to a product called Drobo.

At first, it didn’t seem to fit in with what I wanted to do, primarily networkability and an SSH interface. But after watching the demo, I was sold. I was going to make it work somehow.

Drobo is intended to plug into your Mac or PC as an external USB drive. To your computer, it looks like any other external storage device, but while it just appears a chunk of capacity, Drobo uses a hot-swappable pseudo-RAID approach internally to protect data and provide extreme flexibility for future expansion.

That said, Drobo only officially works with Mac and PC. You can format it in their mutually incompatible filesystem formats; HFS+ and NTFS respectively, or share it between platforms with the old FAT32 standard.

To mount it under Linux, I had to choose to use either FAT32, NTFS-3G on FUSE, or ext3. In order to get the ext3 support, you’re supposed to use the DroboShare, which costs an extra $200.

Instead, I used that money to get two 500GB hard drives and approached ext3 support a different way. I connected the Drobo to my Linux server and formatted it as I had for the new drive I mounted internally last year.

This meant that the storage isn’t directly accessible on the network, but I could easily share it out via the server. This also makes backups from the server faster.

Following are the steps I took:

  • Unbox the Drobo and put in two drives from Newegg. (Western Digital Caviar SE16 WD5000AAKS 500GB 7200 RPM SATA 3.0Gb/s Hard Drive – OEM).
  • Plugged it into my Windows XP machine to check for firmware updates, not to format the drive. There were none so I could have skipped the step.
  • Plugged it into my CentOS 4.6 Linux server, then ran lshw to find the device name (/dev/sdc).
  • Entered the following commands to format the drives and mount the Drobo at startup:
    [root@192.168.1.1]# /sbin/mke2fs -j -i 262144 -L Drobo -m 0 -O sparse_super,^resize_inode -q /dev/sdc
    [root@192.168.1.1]# mkdir /drobo
    [root@192.168.1.1]# mount -t ext3 /dev/sdc /drobo
    [root@192.168.1.1]# vi /etc/fstab
            /dev/sdc   /drobo  ext3    defaults     0 0
  • Reboot and chown’d the filesystem to my rsync user name.

Everything seems to work well for now, but I’ll post an update when I add capacity later this year.

I suspect I’ll have to make some changes in the future, but for easily adding expandable protected storage to a home Linux server the Drobo is a highly recommended option.

Another tip from Kashif: use the promo code “Cali” when checking out at drobostore.com to save $50.

  

28 Responses to 'One week with the Drobo on Linux'

Subscribe to comments with RSS

  1. Douglas Willcocks said,

    17 March 2008 at 4:27 am

    Hi,

    I’m also thinking about using a drobo on a linux box. I know it’s only been a day, but have there been any hiccups so far? Also, does the drobo appear as being a 2TB disk as on supported platforms? Or do you see the “real” storage capacity?

  2. Daniel Krook said,

    17 March 2008 at 7:00 pm

    Hi Douglas,

    Yes, it shows as 2TB. Here’s the output from df -h:

    /dev/sdc 2.0T 66G 2.0T 4% /drobo

  3. Daniel Krook said,

    17 March 2008 at 8:12 pm

    Also, no hiccups so far, but just a heads up; I was originally a bit hesitant to do this based on what seemed like a lot of folks having inconsistent results on the forums at drobospace.com.

    Mark from Data Robotics had the most important piece though, the mk2fs command with the proper options. This command is what the DroboShare uses under the hood.

  4. Douglas Willcocks said,

    18 March 2008 at 3:20 am

    And what about the blue status lights? Are they useless as the thread suggests?

    If so, I may as well just skip ext3 and use HFS.

  5. Daniel Krook said,

    19 March 2008 at 12:05 pm

    Douglas,

    There are 2 lights on right now, with the 66GB across the 2 500MB drives. Whether they go out if and when that 66GB is removed, is another question…

  6. Mike said,

    11 April 2008 at 9:06 pm

    It’s been a month now. I am about to format my Drobo to ext3. How have things been going?

  7. Daniel Krook said,

    17 April 2008 at 2:46 pm

    Hi Mike,

    Things are still right as rain. No problems so far.

  8. Mike said,

    28 June 2008 at 12:39 pm

    I purchased my Drobo about 2 months ago and have to say its one of the best purchases I ever made. I love being to drop files onto it and not have the worry that they will ever be lost. Using etx3 as well. Thanks for this post, without it I would probably not have dropped the money to buy Drobo. :)

  9. Mike said,

    13 July 2008 at 11:37 am

    Hmm, did you ever need to or figure out how to access Drobo formatted ext3 from Windows?


  10. 14 July 2008 at 1:23 pm

    Thank you for the article my newly installed Drobo is in place and happily acting as the backup drive for the other servers on this network. Great stuff thank you.

  11. Daniel Krook said,

    15 July 2008 at 8:31 am

    @Nicholas, excellent, great to hear it :)

    @Mike, thank you. I have not needed to access the ext3 formatted Drobo directly from Windows, but I do share the space out via Samba from my Linux server.

  12. slonkak said,

    14 August 2008 at 12:02 am

    I just got a FW800 Drobo with 2x250GB drives. I configured it as you described and it’s working great. Have you added another drive to it yet? I’m wondering since there’s no helper app like on Windows if it’ll pick up a new drive seeing as it wasn’t there for the original format.

  13. slonkak said,

    14 August 2008 at 12:19 am

    Also, do you know how to determine the serial number of the device from within linux. I’m sure, as all devices, the hardware can be “read,” I just don’t know how.

  14. Iddo said,

    15 August 2008 at 8:22 pm

    Daniel,

    Thanks very much for the tips. I bought a Drobo, 4 disks, 1TB each. After going through your instructions for ext3 formatting, I now have appears on my ubuntu box as two devices (sdc and sdd) of 2 TB each.

    My question is: if Drobo’s beyondRAID were functional, wouldn’t I have a lot less physical disk space available? The drobolateor lists a phycial configuration of 4TB as having only 2.7TB disk space. http://www.drobo.com/Products/drobolator.html

    Can you please elaborate on how beyondRAID works in ext3 (if at all)?

  15. uneekvu said,

    25 August 2008 at 9:58 pm

    I am wondering if you format 2 drives in ext 3, then a year later you decide to add another drive, what would the fromat of the 3rd drive be in?

  16. koitsu said,

    06 September 2008 at 6:28 am

    The Drobo is such a great product… except when you get down to the technical details, which is why I continually avoid buying one.

    Drobo should really not have any idea of filesystems. Do RAID controllers have any knowledge of the underlying filesystems? No, and they shouldn’t. With that in mind, if Drobo needs some way to store its own metadata (for whatever reason, don’t ask me why) on those disks, since the Drobo itself handles all the LBA/CHS addressing and knows how large the disks are, then it should be able to chop some blocks off the end of each disk (decreasing overall available space per disk, but solving the problem).

    Here’s the bottom line when it comes to what consumers want:

    I should be able to insert four 1.5TB disks into Drobo and have approximately 6TB of usable disk space. I should be able to use ext3fs, ext2fs, reiserfs, Solaris/FreeBSD ZFS, FAT32, or any other filesystem I want — and the space limitation should be because of the filesystem, ***NOT*** because of the physical device (Drobo). If the filesystem I choose has a 1GB boundary, then so be it! Drobo shouldn’t care.

    Is what we want possible? Yes, absolutely. The question is really why Data Robotics didn’t do it this way.

    I’m also saddened by the fact that Data Robotics continually totes the Drobo as “working without any software”, when in fact you *do* need a driver on Windows and OS X to properly administrate and get information from the Drobo. The forums are now closed to guests/non-regged-users, but there are hundreds of posts there talking about how relying solely on the front panel lights is not enough while under Linux, and how the lights are sometimes wrong (when using ext3fs… while if you use HFS+ under Linux, somehow that makes everything work fine). This just further proves my point.

    I hope Data Robotics eventually figures this out, because really that’s what consumers want. For now, I’ll stick with PC cases that have 8 hot-swappable drive bays (Supermicro makes many), and a 8-port SATA (not RAID!) card, using OpenSolaris or FreeBSD with ZFS.

  17. Stephen said,

    11 September 2008 at 12:14 pm

    Drobo on linux – my experience so far.

    I bought a Drobo, 4 disks, 1TB each. In order to get a single disk (Drobo splits up the disks, what ever size you have into multiple 2TB drives) I created a logical volume group with the two drives (/dev/sdc , /dev/sdd) using pvcreate. Then created a Logical volume with lvcreate. After creating the filing system (ext3) I could then mount the volume. This gives me 2.5TB of disk space mounted on a folder.

    I then spent a while filling the Drobo up, right up to 2.5TB – all the blue lights on and a red light on the top disk. I wanted to test its redundancy at this point so I pulled the top disk out, I could access the data with no problems. Pushed it back in again, it happily rebuilt its drive (it still complains about being too full at the end though). Having tested it I deleted all the data, unfortunately the blue leds did not go out. Presumably because it does not understand ext3 it cannot calculate the disk space used.

    This has lead me to wander, if the Drobo thinks it is too full will it slow down deliberately as the manual suggests? Have not tested this yet as I only read this after I deleted all of the data that took 2 days to put on.

    Although it looks quite nice I think in hindsight I would opt for a more standard external raid device (unless they come out with Linux support soon). Having said that if you are using it under Windows it seems to work without any problems.

  18. Mark said,

    15 September 2008 at 7:16 am

    Thanks for the article. Just got a pair of Drobos (for fault-tolerance) and will soon set one up on Linux. Shame about the space reclamation issue but that’s not a disaster, though I hope there’s a workaround someday.

    @koitsu – I believe Drobo uses storage virtualization and thin provisioning techniques (wikipedia has explanations if you need them). It does not present the physical disks to the OS – it presents a virtual representation of the disks. It needs to understand the filesystem in use in order to do this, thus the limitation on supported filesystems.

  19. philobyte said,

    29 September 2008 at 11:18 am

    hi folks,

    You might want to check out the drobo dashboard I wrote:

    http://drobo-utils.sf.net

    It also has a link to the google groups where there is a lot of talk about using Drobo’s under linux. Drobo’s actually work fine with 2 TB ext3 file systems. and the droboshare unit is an embedded linux.

    google group:
    http://groups.google.com/group/drobo-talk?hl=en

  20. Hylton said,

    10 October 2008 at 12:43 pm

    I totally agree with koitsu.

    I am looking to purchase a DROBO for a single user use who uses openSUSE 11.0 but from what I have read here, this product is not power consumer friendly ie ‘the drives must still be formatted after being inserted. Why can’t the Drobo assess what OS is using the thing and format the drive for that OS?
    P.S: I have heard that the DroboShare is being discarded and Ethernet is going to be incorporated with FireWire/USB on the rear of the unit.

  21. James said,

    10 October 2008 at 4:34 pm

    Hylton,

    If by formatting you mean putting a filesystem on, eg HFS+, NTFS, EXT3 – then the answer to your question is that this is the OS’s responsibility, not the peripheral’s.

    I’ve been using a Drobo v2 with Linux (Ubuntu) for a few days now; it works very well so far, I’m happy to say. It’s loaded with four Seagate 1TB drives. Although I only have ~3TB of usable space, the Drobo provides two 2TB partitions – so that either of the two EXT3 filesystems I’ve established can grow to 2TB.

    I still don’t know what will happen if I fill one up then attempt to write more than 1TB to the other – I think that the OS will attempt to permit this of course, since it will believe that it’s writing to a 1TB partition. I’m guessing I’ll get a write error, or a hang – but Drobo support haven’t told me yet. Waiting for their reply.

  22. James said,

    10 October 2008 at 4:34 pm

    s/writing to a 1TB/writing to a 2TB/

  23. ~S~ said,

    26 November 2008 at 12:30 pm

    @James

    When you reach the full amount of physical space the process writing to Drobo just hangs. I left the process hanging for some time and then deleted hard drive space and the process went on it’s way copying data again.

    I posted my results on the Google groups site (posted above) if you care to read more of the tests I have done.

  24. wires said,

    18 June 2009 at 6:50 am

    iSCSI and FW800 don’t work reliably on the DroboPro under linux (yet).

    USB works, but this is really suboptimal… ~22MB/s

  25. Tom said,

    24 June 2009 at 3:45 pm

    I have had a drobo for a while now and formatted it using the NTFS file system. I have had no problems, but would like to use your dashboard from my Mandriva installation as well. I am a relatively new Linux user and “tried” alien to no avail. Can you offer any suggestions, or possibly an RPM version of the download?

    Thanks!

  26. Dave said,

    08 January 2010 at 9:25 pm

    So, thought I’d add my own experiences and warnings here, since you did a good job with the original post and the updates:

    I bought a Drobo in June, 2008, and had it hooked up to a Windows XP PC and formatted NTFS. After expanding the capacity a few times, I ran into the 2TB NTFS max-volume size. Rather than splitting the drobo into multiple logical drives, I formatted it as EXT3 and mounted it to a Linux (Ubuntu) PC.

    After the initial headaches of getting the Drobo formatted correctly, everything was great. The blue capacity lights reflected the current capacity correctly, and adding additional drives was no problem.

    Then the Linux PC it was connected to started having problems.

    The PC would freeze often, and after several hard reboots the ext3 journal got messed up. Being a relative noob in Linux, I assumed the drive was FUBAR, and eventually reformatted, losing several hundred GB of data.

    As a remedy I rebuilt the Linux PC with some newer hardware (and better cooling), and put it and the Drobo on a UPS (although I’ve heard the Drobo actually has a small UPS on-board). For ~6 months this worked fine, and then I got ambitious.

    I built a new media PC to replace the Linux system that the Drobo was attached to, and planned to use a ext2 driver for Windows to connect the Drobo to WindowsXP. At some point during this process, the ext3 journal has again been corrupted.

    Since I currently have about 4TB of data on the drive, I am incredibly hesitant to reformat it. Instead I’ve done some homework into rebuilding the journal on a ext3 filesystem.

    On running e2fsck on the Drobo, I get the error that the Superblock is corrupt, and suggesting to run e2fsck with an alternate Superblock. Running mke2fs (sudo mke2fs -n /dev/sdb1) gives a list of all the Superblocks, and eventually one of those blocks will allow e2fsck to do its thing (which usually takes about 6 hours if I’m on top of the prompts, running in the automated mode gives an error). Afterwards e2fsck says the drive is fine, but it still won’t mount. After rebooting both the Drobo and the PC, I’ll be back to the start with e2fsck reporting a bad Superblock.

    FML.

  27. ajames said,

    20 December 2010 at 11:44 pm

    Great write up! Could you add instructions on how to get it working with MythTV? :)

    -Albert

  28. warren said,

    22 December 2010 at 5:36 pm

    what if i want to nfs mount drobo from the network using ubuntu linux

    SO FAR WHat i did:
    ububtu desktop client
    drobo : //drobo-test/drobo-fun-test
    installed: nfs common portmap
    vi /etc/exports with IP address of drobo (rw,rsync)
    mkdir /drobo-fun-test

    do i need to vi /etc/fstab? and what do i need to put in there

Leave a Reply