Controlling SO_RCVBUF

[David Wilson]

On Thu, Dec 12, 2019 at 12:00:40AM +0000, Robinson, Herbie wrote:

> I have a customer who is complaining about slow SFTP transfers over a
> long haul connection.  The current transfer rate is limited by the TCP
> window size and the RTT.  I looked at HPN-SSH, but that won't work
> because we don't control what software the peer is using.  I was
> thinking about coding a much more modest enhancement that just does
> SO_RCVBUF for specific subsystems.  In the interest of adding
> something that the OpenSSH community would take back into the source
> base, what do people think is a better fit in the configuration file?

It is possible to simply tweak the kernel default instead, at least on
Linux (tcp_rmem). Is this not workable in your case?


David