To be honest my comments about FusionDrive is only an assumption. If you still have the option to partition the drive then there is no reason why it shouldn't work, the only difference would be that files on the new partition would not be able to move over to the flash storage for increased performance.
I decided to jump the gun and partition my Fusion Drive. Guess what? I can't seem to be able to partition it. I have more than 500GB free, but when I attempt to partition the main HD (Macintosh HD), all the options appear greyed out.
and, while the "+" symbol does seem to be available and one can click on it, whichever size I decide to adjust, the system will complain saying that the disc is too small "The target disk is too small for this operation"
I've visited this http://support.apple.com/kb/HT5446?viewlocale=en_US&locale=en_US and it looks like I should be able to partition, once at least, my HD.
Man, this is all but "It just works". I just got off the phone with Apple, and tomorrow I'll have a second call conference programmed. It looks to me as if Apple likes to make things a little overcomplicated lately. I also have one case opened with them because I can't use Back to My Mac at all (and they are asking me to fumble around with ports and stuff) while others, aka LogmeIn for example, seem to have this stuff rather good solved, and they've managed to overcome all this burden quite easily.
Sorry to moan a little, but I'm rather annoyed.
We have 3 iphones, an iPad, and an iPad mini between 3 of us (husband, wife, young teen) and all 3 phones photostream to one iphoto library on our MacBookPro, using the same Apple ID on all mobile devices.
The 3 phones have seperate email accounts, one even has a different Apple ID for email, addresses, etc.
We do NOT photostream from the MacBookPro main library to the mobile devices, only from mobile to main.
It works, but not sure I could tell you how!
I managed to figure out my own problem, and I feel I'm dumb. It turns out that the Trash contained lots of files and that prevented my system from being able to even start partitioning the hard drive. And I ask, is the message displayed in my previous post indicative of such a thing? Apple, what's wrong with you guys?
But wait, those are not the good news. If you try to partition a Fusion Drive at this point in time running version 10.8.3, you will end up with an incorrect sized partition. Apple, what's wrong with you guys?
... and should you attempt to modify the size, the GUI is hopeless. After a lot of work, I managed to partition the drive just fine following this http://forums.macrumors.com/showthread.php?t=1500361&page=2
Apple Support was clueless and insisted I should format my computer. I'm a little disappointed with Apple Support because you would expect you would be assisted by a real expert, but all they do is ask you to reformat your computer as soon as they can, when simply the Trash may be the culprit... And of course, they were clueless with the partition size thing, and even though they provided that link to macrumors, they wouldn't certify that information was accurate, nor would they even confirm that by reinstalling and reformating my computer, my problem would be solved... AppleCare these days seems to be useful for hardware stuff only, but phone support has become pretty limited/useless (my personal opinion).
Anyway, I strongly recomend that thread from macrumors. Right now my iPhoto Library lives in a new 200GB partition and I don't need to fumble around with external hard drives or disk images. But setting up the environment requires some technical background and running some Terminal commands. This is not "it just works".