What can I do to speed up SSH SFTP transfers


#1

I am using the SSH functionality to backup files from my server to my PR4100 and seeing that the speed difference between a normal WIndows copy/paste of a large file is about 5 times faster than using the SSH method so what can I tweak in the PR4100 to boost the SSH performance? Obviously my SSD and the network are not the problem since I can achieve near 1Gbps with the Windows copy/paste method. Have done the test using multiple PC’s, all high powered and using SSD’s, all render the same results. So here are the stats of the different methods:

  1. Windows copy/paste = Average 950 Mbps
  2. SSH using the program WinSCP = Average 185 Mbps
  3. SSH using the program FileZilla = Average 190 Mbps
  4. SSH using the Renci C# dll and my own custom code = Average 215 Mbps

So what is the deal here, I know that there is some overhead with SSH due to encryption, but to slow down the transfer by pretty much 5X, thats insane. Hope someone has run across this and found a tweak or fix.


#2

Check if the CPU on the windows host is not saturated.
Install entware and use htop to monitor load on the PR4100. Eventually try the ssh daemon from entware on another port (not 22).

Some extra info https://gist.github.com/KartikTalwar/4393116


#3

Thanks for the reply. As I stated the PC’s are high-powered and have no issue at all, the apps use on average about 8% CPU while transferring. I will look into entware, not familiar with it so I will look it up.

EDIT:
Just loaded up the main page of the PR4100, forgot that it had a memory usage and CPU usage live chart. Just sent a 4GB file and the highest the CPU got to was 41%, Memory is at 31%, during the few minutes it took to transfer it.

EDIT2:
So I force the encryption to arcfour256 and pretty much all apps doubled in the transfer rate so that is something.