"4TB? That's $60 per month. Mmkay. Just use duplicati + cloud cold storage. Way cheaper." This is random access, live storage - which is not the case with cold

"4TB? That's $60 per month. Mmkay. Just use duplicati + cloud cold storage. Way cheaper." This is random access, live storage - which is not the case with cold storage options such as Glacier. A more fitting comparison would be S3 ... I think you are, in many cases, correct - offsite backups can, indeed, be write-once ... but if you're looking for the very specific efficiencies and features that zfs-send affords you, that will not be the case.