Where to backup my NAS

Existing setup;

3TB WD MyCloud NAS with personal files (backed up to USB drive)
5TB Seagate Personal Cloud NAS for movies (dead, but backed up to USB drive)
5TB USB drive with movies on (not backed up)

Want to have one NAS for everything, with movies streaming via Plex, and personal files backed up to my OneDrive account and accessed via laptop. I had been looking at the Synology DS418play, with 2 x 12TB drives, and also reusing 2 of my existing USB 5TB drives (removed from enclosures), to give me more space to expand my movie collection in the future. Using Synology SHR, this would give me a decent amount of storage, and include redundancy/backup and the option to switch drives for more space later. My main concern is the backup of this. I had thought an SHR setup would be sufficient backup, but after reading tonight (and my misunderstanding), this and RAID should not be used as backup option.

I don’t fancy backing up this amount of data due to cost – if even possible without replicating the above setup. Any thoughts/solutions on the above?

Yes, DS418play will allow you to stream via Plex and also allow automatic backup to your OneDrive account. I would rather recommend using BlackBlaze as your backup solution for your NAS because there is no size limit what you can back up (or mix both).

If you mix 2×12 and 2x5TB your available storage will be around 22TB (12TB lost for redundancy). It will work, despite that its recommended mixing similar kind of drives like WD red or Ironwolf.

And yes, RAID is not a backup. There could be a disaster like a flood, fire or burglar taking your NAS. But if you have at least a cloud backup or local external HDD backup, your data will be safer.

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Of course I would prefer you choose AMAZON UK AMAZON USA to buy your perfect solution, however, if you would rather buy locally, please use the links used above to take you to your local Amazon store and help support this free advice service with ad revenue. More ways of supporting the blog are described HERE  
Home: https://www.backblaze.com/cloud-backup.html#af9rgr Business: https://www.backblaze.com/business-backup.html#af9rgr Comparison with other service providers: https://www.backblaze.com/best-online-backup-service.html#af9rgr   For backing up your NAS do consider BackBlaze. You can try it for 15 days free if you don't believe its good. But the main reason is unlimited backup size. Everyone else like Dropbox, Amazon, and others charge per gigabyte. But  with this one there is no price difference either you backup 2 bay or 8 bay NAS. The other great feature is version control. So even if you get hit by ransomware type of virus or simply deleted or mistakenly changed few files. You can restore your data from historical backup versions and get all data back.
You can get it for free here and try:
Home: https://www.backblaze.com/cloud-backup.html#af9rgr
Business: https://www.backblaze.com/business-backup.html#af9rgr
Comparison with other service providers: https://www.backblaze.com/best-online-backup-service.html#af9rgr