[mitchellh]

I understand you use the rsync approach since its similar to how you actually deploy, which is completely understandable, but I just wanted to note that John and I struggled with the shared folder performance issue + Vagrant for months, and we did a LOT (months) of real world tests with various solutions (John at one point even integrated background automated rsync directly into Vagrant), we found that NFS is really the only satisfying solution (for us, at least).

NFS allows us to edit code locally on our host, and have it "instantly" be ready on the guest. After just half an hour of working, the various inodes are cached on the guest and file system access over NFS is mostly native-speed since it only needs to grab changed pieces.

The end result: We completely ripped out background rsync despite John working weeks on it, and we put in built-in support for NFS, which has been going strong since around July now and is happily at work at many places that use Vagrant :)