sftp backend establishes a new connection for every action

[Max Kanat-Alexander]

duplicity 0.6.08b
python 2.4.3
CentOS 5.5

When using the SFTP backend (really the scp:// backend, but I suppose they're the same now), duplicity creates a new connection for every single file that it wants to download or upload. For the manifest and signature files in particular, this can add 30 minutes to a backup process. Since SFTP is a persistent protocol and initial session negotiation is slow, it would probably be faster to just make the connection once and then issue commands over it, instead of re-making the connection for every upload or download.

[Laszlo Ersek (lacos-caesar)]

Consider starting "ssh -M -N" separately first, and adding "ControlPath /tmp/ssh-socket-%r@%h:%p" to your ~/.ssh/config file, in the appropriate Host section. This should result in a single ssh connection (negotiated only once) and each file transfer should create a new session only (inside the preexistent connection).