Huge mistake-almost 3Tb lost!!

It has to format the disks to use them. The OS partition is stored on all disks and the data volumes use the BTRFS filesystem. Where did you read a comment saying that after the first two drives, the other ones are just data? That is certainly inaccurate.

You could try data recovery software, but I doubt whether it would recover anything.

I found it on the Netgear website. There is no accounting for stupidity on my part, but I am now looking to see if it is recoverable.
When I took the drive out of the NAS, My computers are not recognizing now.

http://kb.netgear.com/app/answers/detail/a_id/22802

Where does that article say after the first two disks, the additional ones are just data? It says that adding additional disks will increase your storage space, but that's because with say two disks, any one disk fails data remains intact, and with four disks, any one disk fails, data remains intact. With two disks it is similar to RAID-1, whereas with more disks it is like RAID-5.

This is what I thought it meant to be able to add drives. I didn't expect it to format without me saying so.
Quote from Website: (Instead, with X-RAID, your volume automatically expands to accommodate additional disks or larger-capacity disks.)

Thats talking about backing up the data on the NAS already. You can add additional disks without needing to do a backup of the data already on your data volume (though it is advisable to maintain a good backup as things can go wrong with RAID).

With say a RAID-1 volume if you want a larger volume you have to delete your volume (wipes all data) and create a new one. With X-RAID you can add a disk, it will be wiped and added to the array and your volume will expand automatically.

Bummer. Yeah, as mgdm mentioned, you could try and use some data recovery software, but it doesn't look good. The idea with RAID is that the disks, although independent, work together to keep your data safe in the event of a disk failure. Without going to far into details, this is done through a combination of "striping" (writing your data across multiple disks) and/or "mirroring" (writing an exact copy of your data to all of the disks) and often leverages some type of error checking to reconstruct missing data ("parity") if required. So by necessity, the new disk needs to get in sync with the rest of the array in order to store the striped, mirrored and/or parity data, etc. Otherwise, it wouldn't be adding to the redundancy of the array. X-RAID hides the details of how to do this (formatting, etc). I think what you were expecting was more of a way to "merge" your two data sets together. Unfortunately, it doesn't work that way.

doylmi"]Bummer. Yeah, as mgdm mentioned, you could try and use some data recovery software, but it doesn't look good. The idea with RAID is that the disks, although independent, work together to keep your data safe in the event of a disk failure. Without going to far into details, this is done through a combination of "striping" (writing your data across multiple disks) and/or "mirroring" (writing an exact copy of your data to all of the disks) and often leverages some type of error checking to reconstruct missing data ("parity") if required. So by necessity, the new disk needs to get in sync with the rest of the array in order to store the striped, mirrored and/or parity data, etc. Otherwise, it wouldn't be adding to the redundancy of the array. X-RAID hides the details of how to do this (formatting, etc). I think what you were expecting was more of a way to "merge" your two data sets together. Unfortunately, it doesn't work that way.[/quote]

Yup, I never was trying to put blame, only trying to understand why it happened. Mainly so it didn't happen again. Now it is time for attempting recovery. This one I am going to the professionals. It is going to cost, but stupidity always does.
Thank you, everyone for your help!