I have a suggestion for an added capability for your plug-in (that I love!).
It would be great if you had settings so you could exclude directories and file types from the backup. I have some sub-domain sites in folders under the main site and Snapshot backs up all the sub-domain folders when I use it at the top level. So it is a very large file.
Also there may be .tar or .zip files that one would want to exclude from the backup.