Are you familiar with Drobo? That link gos right to the support page because you are going to need it if you own one. Google "Drobo won't mount, but shows up in Dashboard". Basically, it disconnects and then won't remount but I can see it in the Dashboard app. I can even get it to blink it's lights at me and see it in Disk Utility app. But it won't mount come hell or high water. To fix it I shut down the computer, unplug the firewire cable from the Drobo, wait for it to go to standby mode (one light), then unplug the Drobo power cord. Wait 20 seconds or so and plug the cord back in to power it up. Meanwhile I boot up the compter and launch Dashboard. Once the Drobo is done booting I plug the Firewire cable back in and have 60% chance it will show up. Repeat if it does not. Not exactly fun.
This time after doing this I get some Dashboard red lights saying it's going to take 100 hours to rebuild and data protection is in progress. The tech support person blames the new WD Caviar Green drives. Saying any of them could be bad. So by their logic you are adding more possibilities for failure by having more hard drives in a RAID? Really? Is that not the opposite reason for running a RAID?
I also found out that Drobo uses a proprietary RAID system. So if it does crash, you can't get your data back witout another Drobo bay to plug them into. Not cool. Time to go back to a bank of mirrored hard drives as a back up. One fails I can pull it and still have data. I have been using eSATA Drive Enclosures by Mac Gurus for about 5 years now and have never had a hiccup. Been using Drobo since Sept 08 and have had to call tech support 3-4 times and now I have a serious system crash on my hands that I can't do anything about for 100 hours till it gets done with it's rebuild.
This Drobo does not inspire confidence. If a car keeps breaking down you are not gonna take it cross country on a road trip. The Drobo keeps breaking down, I don't trust it with long term storage needs.
And to people who say RAID is not backup, yeah I know, but it's part of my redundancy here and I use it as my library in Lightroom and iView Media. So shush. The idea of having to rebuild those libraries over the weekend while finding another back up solution to phase out the Drobo is not fun.