I'm booting from a new LaCie Thunderbolt SSD and it won't wake from sleep.

Thanks for the intersting topic. I have a 'late 2012 iMac' base system and can imagine a future upgrade path involving an external SSD using the thunderbolt port.

My WAG of your problem is that Apple's sleep routine disconnects the external HD. If that is the case then I do not see any easy work-around until Apple decides to keep the Finder in RAM. OTOH -- how long does it take to restart the Mac for a RAID ?

Wait, a thought: Try enabling ethernet during sleep. Perhaps thunderbolt is on the same bus ? Your other choice would be to prevent the mac from sleeping during work hours, but put the display to sleep. That throttles down energy use considerably although I cannot give a useful figure for power draw in this state.

I have the same problem with my Mac Pro that has an eSata 6g pcie card and a SSD connected to the card as my boot drive via an esata enclosure. When I sleep the computer for a minute or two it will wake from sleep and continue to work. But if it sleeps for a longer period, the desktop lights back up but everything is locked up except the mouse will still move around or the beach ball comes up, regardless at that pout I have to force shut done the computer and reboot. So it seems like this is not just a thunderbolt issue. It could be one of many things, the eSata card, the ssd enclosure chipset or something on the OS.

Has anyone gotten to the bottom of this yet? I had to return my OWC Mercury Accelsior 2 as it had worse issues.

I installed mavericks on it and every time I slept the Mac Pro and had external esata drives connected to the card, the Mercury would become corrupted and I had to reformat and reinstall the system. I did this about four times then returned it and they are shipping me another. I have a feeling this will happen with the next one.

Sleeping with anything but an internal drive in the internal bay seems to cause issues.

Why on earth are you putting an SSD drive to sleep in the first place? I would say just set the energy saver on the monitors to kick in, don't hibernate the Mac or put the disks to sleep.

"Why on earth" indeed... its called saving energy without having to shut down the computer, thanks but you are stating the obvious.

Don't sleep the computer and the issue is gone! This forum was started to talk about the issue and to see if there is a fix. I use pro tools software and you are never supposed to have sleep settings on, and I don't, but if I go out for a few hours, I like to sleep the computer instead of rebooting. I also have all four drive bays full of esata drives. I can eject all the drives one by one and leave the SSD on and just sleep the screens, but that is more of a pain than just sleeping the computer. The OWC Accelsior 2 pcie drive was getting corrupted as I posted when sleeping the computer when another drive was connected to the esata port, that is a major problem that should not be happening and OWC has a driver that is supposed to allow you to sleep the computer when a system is installed on it, hence why they are sending me another one after speaking with their tech support about the issue.

Perhpas you just can't sleep a mac using an external boot drive period, but I want to here from others that may have had luck or no luck with it. My macbook pro with internal SSD boots really fast, sleeps and wakes super fast and I have a second esata drive installed in it, no issues there at all. Seeing folks are saying the issue happens to them the same way via thunderbolt, and I have this happening vie eSata is interesting.

I have solved my booting issues with the 3TB d2 Thunderbolt 2 External Hard Drives by LaCie.

Bought two of these to use primarily for cloning my main work computers (Mac). The iMac which is about a year old with thunderbolt has worked well with this drive from the start. I partitioned the drive and can clone quickly using SuperDuper which is set it to boot from the drive upon completion to test the clone. My newest Mac Pro has thunderbolt 2. This Mac would not boot a clone on these drives by holding down the option key nor by selecting it as the startup disk from system preferences. I then found the following link regarding thunderbolt performance tips:

http://macperformanceguide.com/MacPro2013-Thunderbolt-performance-tips.html

Even though I have the latest Mac Pro with thunderbolt 2.0, I found that this article solved my problems. Per the article, by keeping this LaCie drive on it's own TB 2.0 bus and plugging other drives into a different bus, I can boot my clones from this drive without issue. Apple has confirmed that the Thunderbolt 2.0 ports are identical to this older Mac Pro.

I experienced no booting issues with USB 3.0 but then I have few peripherals with USB 3.0 which may explain why I had no power issues.

When I contacted LaCie Tech support they basically told me to "go pound sand". Their only comment was that LaCie drives do not support booting. They admitted their documentation does not mention that fact. I've used LaCie drives for more years than I care to count and was very disappointed in their response. The only time I have had booting problems in the past with LaCie drives was when the power adapter was starting to fail. I've not experienced problems when an external boot drive sleeps.