Mounting Drobo b800i on Linux using iSCSI

iSCSI support in the new Drobo is a really neat feature. Here’s how to mount the Drobo as a block device in Linux:

• install some hard disks and connect the Drobo via USB cable to a Windows or Mac computer
• open the Drobo Dashboard and create a volume. I recommend to set it to 16TB size, no matter how many disks you actually have installed. This allows you to grow the filesystem later when you add more disks.
• give the Drobo a static IP address on the iSCSI1 interface and connect it via Ethernet cable to your Linux machine (directly or using a gigabit switch)
• unplug the USB cable
• in Linux you need to install the iSCSI daemon. On Ubuntu just become root and run apt-get install open-iscsi
• make sure your Ethernet card is configured to be on the same network as the Drobo
• run iscsiadm -m discovery  --type sendtargets --portal 169.254.2.0 where the IP address is your Drobo iSCSI1 IP address
• you should now see your volumes listed, like 169.254.2.0:3260,0 iqn.2005-06.com.drobo:b800i.tdb1119b0269.id1
• connect to your id1 volume by running iscsiadm -m node --targetname iqn.2005-06.com.drobo:b800i.tdb1119b0269.id1 --portal 169.254.2.0 --login
• run dmesg | tail to see whether the block device was detected by the Linux kernel
• run parted /dev/sdb to partition your device. Use mklabel to create a GUID partition table (GPT). Then use mkpart to create a partition. Drobo apparently does not support ext4, but ext3 works fine for me.
• the block device will appear to be of size 16TB. However your actual useable space depends on the number and size of the disks you are using and the amount of redundancy you selected. Make sure that the partition you create is smaller than the actually available space. You can calculate the capacity of your Drobo here. Leave the rest of the 16TB disk as free space.
• exit parted and format the disk using mkfs.ext3 /dev/sdb1
• mount /dev/sdb1 and enjoy blazing fast storage
• for automatic iSCSI target login on boot, run iscsiadm -m node -T iqn.2005-06.com.drobo:b800i.tdb1119b0269.id1 -p 169.254.2.0 --op update -n node.startup -v automatic
• If the target login fails, it helped me once to disconnect the USB cable
• If the Drobo volume should mount on boot, add an entry to the /etc/fstab with options auto,_netdev