Backup over SFTP (SSH) works, just really SLOW

Getting anywhere between 32 to 36 Kbps. The connections between these machines is 100 Mbps up and down (fiber internet FTW).

The only bottlenecks I can think of is the destination computer itself (it’s a model B Raspberry Pi) and of course the fact it’s running over SSH.

I need the transfer protocol to be secured, and I need the receiving computer to be tiny.

That all being said, anyone here use the SFTP option? Are they getting better results than me, then what destination computer are you using, have you changed any SSH options to speed things up?

Can you try using some standard SFTP tool (like Cyberduck) and transfer a few large files to see what speed they give?

If you do not get good speed there, you need to start the debugging on the SSH layer. If you get good speed, there is a chance that the SFTP client in Duplicati has some issues with your setup.

If you run a command such as this on the RPI:

/usr/sbin/sshd -p 4455 -D -d -e

It will start an sshd instance in debug mode on port 4455 that prints debug info into the terminal.

Try sending files with something like Cyberduck first, then try again with Duplicati and compare the two logs to get an idea of what they are doing different.

I know this thread is old, but what I found was putting the backup target on a Pi 3 vs a first gen Pi made all the difference.

If you’re going to backup to a SFTP target, the CPU speed matters.