This from the LaCie website:
"Both USB and FireWire put a small amount of electricity through the connection. The automatic power switch on LaCie drives works by measuring power changes in the data cable.
Unfortunately, not all computers change the amount of power coming from those ports. Many keep the power on so it is possible to charge USB devices (cell phones, mp3 players, etc.) while the computer is off.
As the power amount doesn't change, the drive is unaware when to shut down.
Verify this by shutting down the computer, then unplug the computer from power for a while. The drive will shut down when the power stops coming from the ports."
I also checked Energy Saver in System Preferences and "turn hard drives off" was checked, so maybe Mavericks has changed the voltage level on the Firewire port during Sleep, and the drive stays on. It's been turning off for 3 years.
I too am having similar issues but with my ministacks. My ministacks would go to sleep with all previous versions of OSX, excluding Lion as I never used Lion. The ministack would go to sleep if the Mac has not read/or written to it after a certain amount of time, not just when the Mac goes to sleep. Most likely it works just as stated above with a voltage comparison.
OWC informed me that I had to have the USB cable connected for that feature to work but I have not had the ministack on my iMac plugged in USB for some years now and the sleep mechanism has always worked. As a mater of fact the ministack went to sleep with just firewire while I was on the phone with the OWC tech support but it only slept for about 30 sec.
This must be a Mavericks issue. I have tested this on two diff iMac and 2 dif MBPs. The drive just does not sleep with mavericks.
I guess that we're now going to be forced to equip all our externally attached drives with server grade drives as they will be running non stop.
I got notice from OWC that they just tested my drive with the latest Mavericks release OS X 10.9 (13A603) and the drive failed to sleep via Firewire. They told me that they were trying to see if they can fix the issue on their end, but as "ssls6" stated it appears as it is a Mavericks issue and hopefully Apples next 10.9.1 or 10.9.2 release would fix the issue.
So it would definitely be worth contacting Lacie to see what they can discover.
I've sent a bug-report to Apple Feedback.
They don't follow every post on the forums so it never hurts to tell them directly when something's wrong. I hope they fix this.
This is a known issue to Apple for a while now. Firewire and Thunderbolt external drives will not go to sleep, even if ejected the drives will continue to spin and possibly overheat. The option is to use the USB port since those are not affected. Some of those larger external drives my only have a thunderbolt and no USB hook up at all, so in the case you will need to turn off the external drive manually after ejecting it.
There is also a sleep issue with the USB drives if your external drive is encrypted. If it is then that drive will not sleep either even if you use USB. Mavericks has several other bugs even one big one with SSL that could comprimise security if your on a public wifi network.
Mavericks 10.9.2 beta is out but when will it be ready for us to get it is unkown. Will it address the Firewire/Thunderbolt external drive not sleeping issue unkown. I am guessing the big thing it will address is the SSL issue.
Should of stayed with Mountain Lion is all I can think of.
Same issue here - now with 10.9.2. My Lacie D2 is continually on, even though it is only used for backup. I ejected it, but as soon as the iMac woke again it powered the drive - but it isn't visible on Finder any longer. I don't even know whether the back-up will work (I know I could try, but don't have time right now).
The other issue I had was my other drive (iomega eGo) was frequently ejecting for no obvious reason. I had tried everything I could to change settings, but hadn't yet found this and other threads pointing to issues with Firewire. If I had, I may have saved the drive - it finally failed yesterday and I don't know whether it was from being ejected incorrectly or from overheating (or something else).
It seems as though I will have to change my drive connection from Firewire to USB2.0, hopefully only temporarily because it is a big step backwards.
Looks like Apple might of given up an a fast resolution on this issue. They called me to help me change back to Mountain Lion. I did not have time to do that at the moment they called me but this can't be a good sign. I have some time next week so I will be calling them back to go back to Mountain Lion.
Last I heard it has something to do with the "Wake For Network Access". Everytime drives are going to go to sleep this keeps it awake even if you do not have it checked marked to do so. Who knows, the bottom line is that after working with one of the Apple Tech guys for a couple of months thay have yet to find a solution for me other than going back to Mountain Lion.
No clue when 10.9.3 is coming out, hopefully it will fix some of the other bugs people are having with Mavericks such as file transfer on network drives locking or crashing Finder, trouble with periphials, trouble with kernels slowing down the Macs, ect, ect. Mavericks IMHO was not ready for prime time and the free offer just made us all free beta testers.
REMEMBER: You do have FREE 90 day support on OS upgrades even if your warranty is expired.
Just call Apple Care at 1-800-277-5322 with your Mac Serial Number and ask to speak
with a senoir advisor about your issue with 10.9.2.