Strange issue with scp performance

[John-Mark Gurney]

Achilleas Mantzios wrote this message on Wed, Sep 28, 2016 at 13:26 +0300:
> We have a weird situation here. We just made a clone of a virtual image running Linux and sent it over to some could provider. The problem is that the scp performance to *many* hosts in our office 
> center has worsened considerably, including one freebsd box.
> 
> In this freebsd box I run also a jail, and a linux ubuntu image with bhyve. The crazy thing here is that :
> 
> 1) scp from the original (local office center) linux image to the host FreeBSD, its jailed FreeBSD and its bhyve linux is 2.7 MB/s
> 2) scp from the cloud linux image to the host FreeBSD is slow (~300KB/s)
> 3) scp from the cloud linux image to the above FreeBSD's jail is slow(~300KB/s)
> 4) scp from the cloud linux image to the above FreeBSD's bhyve ubuntu is fast(~1->1.5MB/s)
> 
> What can cause this behavior?
> 
> PS
> Please answer to me directly as I am not subscribed to -net.
> Thanks a lot for any ideas.

I worked on this last year a bit, but was never able to track it down.

It may be an issue w/ internal SSH's buffering not growing properly to
handle the latency.

I posted some info on the wiki about this:
https://wiki.freebsd.org/SSHPerf

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."