Did I lose a drive, already?

[Samfb24]

So I built my freenas server last weekend using 6 drives I had around the house. Got it fully up and running with all issues worked out on Monay I believe. Today is now Thursday of the same week and my pool shows it is "degraded". I can only see 5 of the 6 drives listed in the dashboard. And when I navigate to Storage > Disks. I can see all the disks, including the one missing, however that one shows a status of "unused".
Not quite sure what is going on here, did I really lose a drive in a matter of days or am I experiencing a different issue here. There is a possibility the server lost power unexpectedly the other day so I wonder if that is what did it.

 

[myoung]

Give your zpool status, smartctl -a /dev/ada4 and hardware details. How are the drives connected? What kind of burn-in did you do?

 

[Chris Moore]

There is a possibility the server lost power unexpectedly the other day so I wonder if that is what did it.

It has happened that drives fail unexpectedly, I had one in a server at work that just disappeared at 4:43 PM as if someone pulled it out of the server. No warning of any kind. It was still installed, just not showing up in any way. In your case, it would be much easier to offer some advice if we knew what you were working with. Please follow this guide to give us the information we need:
https://www.ixsystems.com/community/threads/forum-guidelines.45124