Help with Synology DS720+ Drives

Good Morning,
I purchased last year a DS 720+. So far it has worked wonderfully with channels. However, being a newbie to synology i didn't understand all of the ins and outs of setting up pools etc.. So I have 2 1TB drives in the system. I wanted to migrate everything that was on drive one (also making up storage pool one) for channels over to drive 2. The reason is I wanted to create 1 large pool consisting of the two drives (also making it easier to expand later). I was able to go through storage manager and get everything moved over using the move feature but it's still showing 3.2 gig being used. Again, this was my original channels storage unit. When i pulled the drive for a test the whole thing stopped working.
Is there a way to see what is on that drive to move it over so i can add that drive and make my pool bigger? I'm still so new with this thing and learning so any help would be greatly appreciated.

I think you automatically lose some storage capacity due to system stuff. So that might account for your 3.2 missing GB.

And by the way, rather than creating one 2 TB pool, you should probably look into setting up redundancy so that if a drive ever fails, you don't lose everything. In your scenario, you would net 1 TB (or really just under) across both drives. It sucks to lose that extra space, but you'd significantly lower your risk of losing data.

Also, since you're new to Synology, I highly recommend googling best practices for security. There are all sorts of a-holes out there who love to try to hack them!