I should clarify, I did not purchase new drives for my new NAS. I need to use the ones I have in the DNS.
Thus, pull a drive, stick into new NAS, copy data over network (probably rsync), then move the other three drives, change from RAID 1 to RAID 5 in new NAS, done. If this doesn't work for some reason, plan B is I move all 4 drives, format everything, use USB drive. This makes me nervous. What if the USB drive decides to crap out?
One of the shortcomings of the DNS is that the only cloud backup is Amazon S3 or you can use that add in for Elephant storage, a company I never heard of. I didn't set that up, thus I have no complete backup. I use Backblaze. There is sort of a workaround. I can run the backup from a Windows machine to get the DNS data up to Backblaze B2 if I want. It's messy but it would work. I did use this method to back up my most critical data but not everything.