I put the tar in /myraid (my btrfs 8 drive raid10) then copy this off to another machine that then replicates to cloud.
So if my boot drive goes out I have the backup on the array, on another onsite machine, and in the cloud.
tar --exclude='/myraid' --exclude='/proc' --exclude='/sys' -czvf /myraid/nas_backup.tar.gz /
I don't have enough cloud storage to replicate /myraid but I copy the entire /myraid mount to another onsite machine with a raid1. I guess its better than nothing :)