I'm the happy owner of a OptiBay since quite some time. An OptiBay Drive Kit replaces our DVD Drive in a MacBook Pro with an SSD or traditional Harddrive.
Since everyone at Liip gets an 256 GB SSD and there was already a 512 GB HDD in it, I got 768 GB disc space in my MacBook Pro, without paying a fortune for such a huge SSD.
I put less often used stuff like videos, music, pictures or archives on the HDD and the often used stuff on the SSD, which always was too small, of course. So I was regularly moving stuff from the SSD onto the HDD. Manual, repetitive labour.
But then, on the last keynote came Apple and introduced the "Fusion Drive". The Fusion Drive is not much more than merging 2 (or more) discs together to one big drive, but it is intelligent enough to keep the often used stuff on the SSD and the not so often used stuff on the HDD. Perfect for my case. And no more thinking about where what should be. And off I went.
I followed more or less this post here.
- Made a copy of both discs with SuperDuper to an external hard drive.
- Rebooted into that copy.
- Deleted the partitions and created a "FusionDrive" as described in the mentioned blogpost (but you don't have to reserve space for the recovery partition, the installer will do it for you)
- Downloaded the Mountain Lion installer from the AppStore, started the installer and installed it into the new Fusion Drive partition on the MacBook
- Used the Migration Assistant to move the data from the copy on the external hard disc to my new fusion drive.
- Copied the stuff from the second disc copy to my new fusion drive.
- Finished - no more moving around and symlinking stuff!
(You could also skip the "make a copy" step and later migrate from a TimeMachine copy, but that's not what I did)
It looks more complicated than it is, but depending on how much data you have to shuffle around, it will take some hours.
I also encrypted the whole thing with FileVault without any problems and as mentioned above, the recovery partition also was created and I can boot into that.
Of course, the whole setup is similar to a RAID-0 setup which means that you double the chances of data loss. If only one disc goes bonkers, all the data will be lost. But I can live with that risk, since I do backups regularly and on different places (thanks to the finally implemented multi-backup-disc feature in TimeMachine in Mountain Lion).
Hope that helps someone, it was definitively worth it for me (as much as I can say that after a few days ;))