Despite repeated housekeeping and backups I was struggling to keep my system healthy with at least 10% of free space. My primary computer, a 13″ mid-2012 MacBook Air, came with a 500GB SSD hardisk. Though blazing fast, the hardisk size is relatively small, and TarDisk reviews were enticing!
There are several options but I decided to end my memory struggle by adding a 128GB TarDisk to the MacBook Air (US$149 = S$215 by Paypal).
The flash drive arrived yesterday and installation was an involved “pearing” process which required decrypting FileVault, running a file system consistency check (fsck), a verification of the hardisk and activation of Core Storage. This saw a few reboots before and after I inserted the flash drive into the SDXC slot to run the app. Just follow instructions; you’ll feel geeky and it will be fine.
Then voila! My hardisk icon had turned to gold (nice move) and the additional memory was presented as a ‘hybrid, fusion drive’. I can’t use Disk Warrior to maintain the directory structure but otherwise, it works like a charm.
Read the reviews on MacWorld and 9to5mac and tour the webpage.
Otterman speaks... 
What a cool review!