new user

If you still have contact with whomever you bought the NV+ from, see if they still have the trays. The trays are an important part of the device, and even if you only install a few drives, all four trays must be installed to ensure proper airflow. If they don't have the trays, I hope you didn't pay very much for the unit, for brand new with a 3 year warranty, they can be purchased on Newegg for $310. The four trays have a value of about $100.

Regardless, what is done is done, and the NV+, although a little slow compared to newer higher powered models is still a very reliable and functional NAS. To the best of my knowledge, every brand of NAS uses it's own proprietary modification of a Linux distro and will immediately reformat a drive when it is initially inserted.

If you still have the Etrayz and it is still functioning, then set the NV+ up with at least one new drive and transfer the files over the network. I would either keep the Etrayz functional for a while, or create a complete backup so that you always have the files on two different devices. Remember that RAID is designed to make replacing a failed drive easy without having to resort to restoring from backup, not as an alternative to backups.