On 2016-11-29, gwes <g...@oat.com> wrote: > I've got 2 6.0 systems: one in BOS one in LA. Transit > time is about 100ms. There's adequate bandwidth end-to-end. > > I can only get 1.5 - 2.5 MB/sec due to the long fat > pipe problem: the receiving system won't open the window > large enough to let the sender put enough bytes in the pipe.
OpenBSD up to and including 6.0 was limited to 256KB buffers, with 100ms RTT this limits you to 2.5Mbit/sec max (second form on https://www.switch.ch/network/tools/tcp_throughput/). Update both sides to -current, it has larger buffers and some other changes to reduce the potential risk from the added kernel memory use. The kernel is normally auto-tuning these days, if you want to force it on a connection you can use setsockopt(). rsync gives an easy way to set this, i.e. "--sockopts=SO_RCVBUF=262144".
