Fusion Drive on my iMac

For Use:
I have the SSD connected via Thunderbolt on my iMac 27 (Mid 2011 12 GB RAM, 1 TB HDD) and set up a fusion Drive (FD). Since I did not want to open and disassemble my iMac, came to me only an external solution in question. Prerequisite for a FD is min. OSX Mountain Lion 10.8.2.

For Explanation:
Fusion Drive called Apple a technology in which a SSD and a mechanical hard disk are transparently connected to a logical drive. The user sees the combination as a single drive. [2]. With Fusion Drive is even with a large storage capacity can be benefits at a moderate price on the speed of the SSD.
Fusion Drive connects not only two physical disks into a single logical, but still used in addition to a technique that is called tiering. When tiering, in German as "staggering", are data that is frequently accessed on the fastest drive (SSD here) saved, the other on the slower, here on the mechanical drive. What data is stored where, the operating system decides on the basis of a thorough analysis of the data access itself and can not be influenced by the user. Optionally coated the operating system in the background to data. The operating system itself is always on the SSD. (Source: Wikipedia)

To set up:
First, a data backup via Time Machine. This is important because on the HDD will be lost when you set up all the data FD.
Time Machine is with me on an external HDD connected via USB.
iMac booted from the external HDD (Time Machine) and the terminal starts.
Here you have to enter some commands. Takes about 2 minutes. For specific instructions, but there are in the network; eg also in c't.
After setting up the FD played backup on Time Machine back and ready.

Conclusion:
The hard drive assembly (Fusion Drive) from the HDD (1TB) and SSD (128GB) achieved now while writing 190MB / s when reading and 390 MB / s (measured with Blackmagic Disk Speed ​​Test).

The boot process now takes just 9 seconds. Word (MS Office for Mac 2011), for example, will now start in less than 1 second; Aperture takes just 4 seconds.
Overall, I practically a new iMac. At least emotionally. The increase in speed is enormous.

The MiniStation is by its Thunderbolt port ideal for such purposes. Especially for people who like a fusion would drive, but be afraid to open your iMac. The external solution does not bother me because my iMac has a firm stand and not going on tour.

By the way, just as quickly as an FD is set up, it can also be removed again.