On 5/30/20 5:46 AM, Anand Buddhdev wrote: > On 30/05/2020 12:32, hw at gc-24.de wrote: > > Hi hw, > >> I'm looking for a good way to create a constant data stream that will >> occupy a >> bandwidth of about 2--5Mbit/sec between two remote hosts over the >> internet. I >> have full access to the hosts involved. >> >> My first attempt to use scp to copy data from /dev/null on host A to >> /dev/null >> on host B, but scp says '/dev/null: not a regular file'. If something >> like >> that would work, I would be able to limit the bandwidth of this >> transfer in >> the router(s) involved so that it won't occupy all the bandwidth. > > You can't read from /dev/null. You get nothing from it. You're better > off using /dev/random, for example. That will give you a continuous > stream of random bytes. I would recommend to read from /dev/zero instead, it will give you a stream of zeroes. Using /dev/random is OK, but has one disadvantage in the OP case: you exhaust machine's accumulated entropy which may be more needed for other tasks (like ssh or ssl connections)... Just my 2 cents. Valeri > > However, that's not the focus of this. You want a sustain a stream of > packets between two hosts. You're better off using UDP for this. And a > good tool for generating such packets would be "iperf". It can measure > bandwidth between two nodes more accurately. > > Regards, > Anand > _______________________________________________ > CentOS mailing list > CentOS at centos.org > https://lists.centos.org/mailman/listinfo/centos -- ++++++++++++++++++++++++++++++++++++++++ Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ++++++++++++++++++++++++++++++++++++++++