Hi Piotr,
> Unfortunately, using 1.5.15 didn't change anything. a few things I would suggest to try/troubleshoot: - try nokqueue mode [1] - try option http-no-delay [2] - check cpu usage (system and haproxy) while uploading - truss ([3]) haproxy while uploading - tcpdump the frontend connection - statically link against openssl, to confirm that the issue happens with both openssl and libressl (README has some suggestions howto compile openssl locally and linking haproxy against it without affecting your system's ssllib) Also can you provide the output of "haproxy -vv"? Regards, Lukas [1] http://cbonte.github.io/haproxy-dconv/configuration-1.5.html#nokqueue [2] http://cbonte.github.io/haproxy-dconv/configuration-1.5.html#4-option%20http-no-delay [3] https://www.freebsd.org/cgi/man.cgi?truss
