AFP breaks when messing with your Public folder!

Oct 4, 2007 · 2 min read · backup dmg ssh ·

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Hi, just a quick reminder to myself and users of the AFP protocol (Apple File Protocol) who are wondering why it is not working. For some strange reason, if you start messing (deleting) the "Public" folder of any user which is on the system providing the AFP share, you will break the AFP protocol.

I just deleted the Public folder from user A because I didn't want that user to have one. When I tried to connect to the server with user B, I got an AFP error. When I removed user A from the system, AFP worked again. I still have to figure out how to granulary disable drop boxes in the future, for now I'll leave them be I guess.

Why all this hassle? Renewed interest in remote backup I guess. I just found out that:

  * You can easily tunnel AFP over SSH
  * If you mount a remote 8GB AES encrypted DMG file, the file will not be transferred in its entirety over the network connection
  * If you write 100kB into the mounted 8GB DMG, it does not write 8GB, but only 100kb+directory update.

According to these observations, it should be able to make a 200GB DMG file on a remote machine, tunnel AFP over SSH and access it as a local disk with reaonable performance, even over an ADSL connection. This will pave the way for an automated rsync backup solution which could actually work, without special tooling or complex scripting.