Dropbox – What Happens to Dropbox Data When Extended Storage Expires?

Desktop folder sync

• Not everyone can sync a (windows) folder with Box.net (yet):

"We are currently rolling out Sync in waves to our Business and Enterprise customers"

• Dropbox sync tool works fine with windows folders
  2 Notes:

  • doesn't work through our corporate firewall.
  • The installation of the Dropbox sync tool doesn't ask for a location: the application gets installed inside your user profile somewhere. Which is too small for our corporate profile.

  But @ home it works just fine!

Answer by Moo at Serverfault:

Dropbox uses a binary diff algorythm to break down all files into blocks, and only upload blocks that it doesn't already have in the cloud. All of this is done locally on your computer.

Dropbox doesn't just use your files that you have already uploaded, it aggregates everyones files into one database of blocks, and checks each local block hash against that database.

This means that if someone else has uploaded the same file as yourself (say for example, the latest Ubuntu iso), then the upload will seem instant as there is nothing to upload, but if you are updating a file that changes regularly, like your backup file, then only the changes are uploaded. If you upload a totally unique file, then you have to wait for it all to upload.