Of the four methods you list, and their &quot;warts&quot;, I would say that duplicity seems the easiest to overcome:<p>&quot;Uses forward snapshots, so recovery takes longer with each successive snapshot, unless you upload a &quot;fresh&quot; copy of the data&quot;<p>(unless you have a relatively slow network connection)<p>duplicity will interoperate with plain old SFTP, so we[1] have supported it since it was released.  We have also contributed funds to the development of duplicity.  In these 10 or so years that it has been around, we&#x27;ve never seen any complaints from customers or evidence of things breaking - it is quite solid.<p>That being said, we do really want to support attic since so many people ask for it.  It requires a server-side component to be run, and we try to keep our environment squeaky clean and dead simple[2] - but I think we can cxFreeze it and run it as a binary executable on our end...<p>[1] rsync.net, with HN-readers discount.  Just email.<p>[2] There are no interpreters in the jail that each account is locked in, so we can&#x27;t run a python component on our end.