I am surprised that there is nothing in Console, as OS X would normally have tried to mount the filesystem, and this did not happen so I would expect an error message.
"fsck" is just the filesystem checker that Disk Utility uses to test/fix the disks. You can actually use the command line version of Disk Utility, e.g.:
sudo diskutil verifyVolume /dev/diskxxxx
where diskxxxx is the device the Drobo appears as - you indicated in your first post that it was showing up.
There are also 'diskutil repairVolume' and 'diskutil mount' commands.
No. If OS X is detecting the disk, then when you plug in the Drobo a new device will appear in the /dev directory as diskxxx. So, if you want to explore, disconnect the Drobo and in Terminal type:
ls -1 /dev/disk*
which will show you what is there now. Then plug in the Drobo (wait for it to power back up if it went to sleep) and then issue that command again. If the Drobo can be seen by OS X, there will be new entries - the disk numbers assigned to the Drobo. The mountable filesystem is probably on the 's2' device, e.g.: /dev/disk6s2.
If no new devices show up when you plug in the Drobo, then OS X is not seeing it at all. No ideas about that.