IMac – Upgrade mid 2011 27″ iMac: replace Superdrive with SSD and create Fusion drive

In the Mid 2011 iMacs (both 21.5" and 27") Apple left enough room for an extra SSD. So if you want to put an SSD inside your iMac you can do that without replacing the DVD drive and/or original hdd. If you're going for an external one you should indeed opt for a SSD with a Thunderbolt connection, otherwise you kinda loose the speed advantage of a SSD.

If you want to separate the OS and application data from your media files, that's entirely possible and there's more than one way to achieve that. Read this and decide for yourself wether it's easy:

• http://www.tuaw.com/2012/01/20/ask-tuaw-how-do-i-setup-a-mac-with-both-an-ssd-and-a-regular-hd/
• http://mattgemmell.com/2011/06/21/using-os-x-with-an-ssd-plus-hdd-setup/

SSDs will only get better and cheaper over time so it can make sense to wait, but since they'll keep getting better and cheaper you could also wait for the rest of your life but SSDs are becoming mainstream now so it is safe to make the jump.

Remember that if you install a SSD in your iMac yourself you will loose your warranty so it may be worth to let an Apple Authorized Service Provider do the upgrade for you. If you insist on doing it yourself you might find the following link useful:

• http://www.ifixit.com/Guide/Installing-iMac-Intel-21-5-Inch-EMC-2428-Dual-Hard-Drive-Kit/6434/1

Good luck!

Personally I did the same thing. No, Cloning and restoring the clone to the fusion drive will not "Destroy" the fusion drive.