AeroFS - File sync without servers

Webrebell was so kind to send me an invite for AeroFS, a new – not yet public – file synchronization service.

I love Dropbox, but it has two flaws: it’s a closed service, so I have to use their servers (and thus hand them over my senstive data), and to gain more than 2 GB storage space I would have to pay money for their servers, while I have some spare space on my own server.

Library setup

AeroFS uses a P2P approach to synchronize your data between your computers. First you have to create a “library” inside of the “~/AeroFS” folder. For each computer you can specify which libraries are synchronized. By default, all libraries are downloaded to new clients, so once you set up AeroFS on a second computer, it downloads the whole AeroFS folder from the first one.

Library sharing

Libraries can be shared with other AeroFS users by clicking “Invite” and adding one or more Email address. This is also the way to invite new users to AeroFS during the private beta.

User experience and performance

AeroFS works in the background, so the user experience is “it just works”. New or changed files in the libraries are synced immediately to the other computers, and as the computers communicate directly, the bandwith is only limited by the two connections (I have yet to test if fast LAN sync is supported in the same network). The AeroFS servers only manage the indexes and the lists of computers associated with the libraries.

However if you add files to your library one one computer, shut down the computer and boot another one connected to your AeroFS, the second computer does not see these changes. This is by design, as there is no server.

The good

  • There is no storage limit, since there is no server. Add as many data as you like.
  • The client program seems to use asymmetric encryption for data transmission. So the central AeroFS servers never see your data.
  • You can choose which libraries are downloaded to which computers.

The bad

  • While there are clients for Windows, Linux and Mac OS X, there is no client for 32-Bit Mac (like my old Core Duo MacBook)
  • AeroFS uses Java. It’s fast and integrates well into the OS but it uses more than 150 MB of memory (Dropbox is like 40 MB). This is barely acceptable (the same problem prevents me from using the otherwise great CrashPlan)
  • There is no versioning (yet). If you accidentally delete a file on one computer, it’s gone everywhere


I like it. It offers great features and I’m sure it will be a nice and secure competitor to Dropbox once it’s finished. What I’d love to see is an open protocol specification, so open-source client (and server!) software can be built, which would allow companies to build their own private AeroFS cloud. Then it would be the synchronization software.

Update: If you’d like to test AeroFS, drop me a comment with your Email address.