Swapping HDD RAID 1 with SSD in Mac Mini I have a Mid 2011 Mac mini with 2x 500G HDD configured as RAID 1.
Recently one of the HDD died. 

I planned to


replace the dead HDD with a 500G SSD, and
let the RAID 1 rebuild


Is this a viable option?

If viable, should I


Leave the setup as is, or
Buy another 500G SSD and replace the other HDD


OS is Yosemite.



Update:

Since the question and the answers, I had went ahead to buy 1 SSD, replaced the disk in the Mini by following videos on Youtube.
The RAID rebuilt without a problem.

The system "appears" to be more responsive than before.
Is it a viable option?

Yes.

You could do either of your options given that you are using RAID 1.  

That said, I am not a fan of software based RAID.  It consumes CPU cycles that could otherwise be used somewhere else.    Given that SSDs are far more reliable than TSM (traditional spinning media), the chances of a drive failure go down significantly.

What I would do is use the SSD as my primary drive and the second hard disk as an internal Time Machine drive.  You will get increased performance, more reliability and much quicker backups