I’ll recommend one more tool I use for off site backup: iBroadcast

I already have a NAS, my original discs / records, and Plex running Plexamp for music streaming, but iBroadcast has been my music locker for streaming / storing in case my home system goes down. You can re-download Your original music and keep the quality (FLAC) so nothing is lost.

Free accounts (which I use) have unlimited upload space but You are limited to 128kbs for streaming. If you pay their monthly (or annual) subscription, you can stream full quality. So it depends on what you want to use them for.

Hope this helps someone!! :)