320GB SSDs cost as mush as 120GB ones did 2 years ago. We'll have affordable 0.5TB ssd's soon probably.
Is there really any use for this? I mean, the fusion drive system would only benefit you if you expect to store more then the SSD can allow. Move your download folder and music folder to an HDD, and you will probably be better off with just a single 256GB SSD which will act much faster then a fusion drive solution.
Remember, the fusion drive puts data on the HDD based on it's own algorithms and what it THINKS you are going to use. In reality you are definately going to find yourself opening alot of stuff which has been moved to the HDD... and then it will be painstakingly slow...
From what i read, things are transferred first to the SSD, then once full, transfers it to the HDD whilst also keeping more frequently used items on the SSD.
All these caching things are useless for a 2TB photo storage drive, because it gets transferred from the camera, worked on, and then forgotten so it would never get SSD'd!
Lightroom benefits most when the raw files are on an ssd.
I don't want a manual operation because that gets tedious. Caching disks don't work, hence why i hoped this might be a better solution if easily implemented.
I currently have a 300GB SSD that holds the OS, cache files, current & recent documents, scratch files and Lightrooms library and preview files.
A 300GB Velociraptior is used for windows.
A 1TB HD stores old documents, disk images, iTunes music library, etc.
Another 2TB disk stores by raw files and all my files are directly transferred there, sent to my backup NAS and then worked on. If Fusion Drive placed the new files on the SSD then as and when transferred them back, without no input from me or change in my backup scripts, that would work a treat.