You're asking if it's possible to install rear disc brakes on your Suzuki Gixxer SF. Well, technically it is possible but we would advice against it for three reasons:

1. Third party installed disc brakes don't offer the same effectiveness as the manufacturer installed ones.
2. Cost involved is very high
3. Suzuki is on the verge of launching a dic brake variant of the Gixxer SF.

Given the above reasons, the entire procedure of installing disc brakes on your bike is just not worth it.