can someone tell me, will this ssd disc work on my mac mini, since is sata 3? As I know my mac uses sata 2?
But I'm really novice and I have no idea.
Yes it will works. It is not a differance, because it is backward compatible. You can find out here more if you are interested about compatibility SATA II vs. SATA III
But one thing you must take in care, that you won't reach speeds of data 3, because your bus only support sata2
Not sure why you think it's SATA2. According to everything I read, the mid-2011 Mini is SATA3
There are considerations related to garbage collection related to the SSD controller. The safest choice is a OWC Mercury from macsales.com since they are intended for Macs. Others may require installing a 3rd-party TRIM enabling utility.