Experiences on Drobo with Linux

OK, I've been troubled by this for 2 weeks....

Some note to keep in track and hope to help others ;)

First of all, Drobo inc. DID NOT CLAIM TO SUPPORT LINUX.

It's not unusable, but there's indeed some limit.

Currently our lab has 2 Drobo S (a bit old), each with 5 3TB harddisks.

This box has 5 bays, max. 4TB each bay, 2 Firewire 800 port (for daisy-chain), 1 USB 3.0, and 1 eSATA port.

The computer pairing with is HP z620 workstation, installed with CentOS 6.3.

Here's the points and experiences:

1.  There's no Drobo Dashboard on Linux. You can set the volume of Drobo with Mac / Windows, and then connect it with Linux box.

2. The only filesystem can be used on Drobo under Linux is ext3. ext4 and XFS? no go, sorry.

3. The maximum ext3 volume size is 8TB. If you have more than that, you'll have to make 2 volumes.

Yes, it can be set to 16TB with Dashboard and the Linux recognizes it. But the Drobo still uses 8TB as volume capacity limit, so it will indicates drive full when the actual data reaches 8TB, and writing becomes very slow.

4. When using 2 volumes, it becomes picky on interface.

5. Using USB 3.0 will present 2 volumes, but factory CentOS 6.3 2.6.32.x kernel can't detect the correct size: the first volume as 8TB and the second 2.4TB only. It can be solved by using kernel-ml (3.7.x) from ELREPO repository, or kernel.org 3.4.x if you really want to build your own.

6. Using (onboard SATA as) eSATA, at least on this HP box, will present only 1 volume. Using the SAS port on the LSI SAS2008 chip card... no volume. (ow!)

7. This computer does not have Firewire 800 port (400 only), so I didn't test this with Firewire.
(Edit: 2013/2/1) Another computer can detect only 1 volume with kernel 2.6.32, but upgrade to kernel 3.4.27 solves the problem.

Note that many distros backport their kernel, so the kernel version may be different on other distros. Another working distro on USB 3.0 is OpenSUSE 12.1, with kernel 3.1.x.

Drobo is overall a good product that supports thin provisioning and great harddisk configuration ability. It is not that good when used with Linux though!

(Our 2 Drobos then become 4 volumes, which is not easy to use. It becomes an adventure on the journey to combine them into one. Challenging that is lol)