Maybe you should have a look on the tcp window size values. I had such a behavior with two gateways who was not playing the same way with the TCP window size which made my network damn slow. If you have a linux gateway in front of your FreeBSD VM, it should be this.
Command Description sysctl net.inet.tcp.rfc1323=1 Activate window scaling and timestamp options according to RFC 1323.sysctl ipc.maxsockbuf=*[sbmax]* Set maximum size of TCP window.sysctl net.inet.tcp.recvspace=*[wstd]* Set default size of TCP receive window.sysctl net.inet.tcp.sendspace=*[wstd]* Set default size of TCP transmit window.sysctl kern.ipc.nmbclusters View maximum number of mbuf clusters. Used for storage of data packets to/from the network interface. Can only be set att boot time - see above. sysctl net.inet.tcp.liondmask=7Used to enable the "netlion" patch above. Cordialement, *Guillaume Seigneuret* *Network and System Security Architect* *Web* : http://www.omegacube.fr *Address* : Hôtel Technologique Marseille Innovation - BP 100 45 rue Frederic Joliot Curie Technopôle de Château Gombert 13382 Marseille Cedex 13 2011/5/12 Laurent Cligny <laurent.cli...@steadinet.fr> > Hello all, > > I want to setup a FreeBSD DomU VM as a network NAT gateway in order to > provide Internet access to other FreeBSD and Linux DomU VMs. > My Dom0 is Xen Cloud Platform 1.0 on a Dell Poweredge 210 with 8 cores, > 16GiB RAM and one NIC. > > All FreeBSD VM are 8.2 amd64 with XENHVM kernel anf the Linux VM is a > Paravirtualized Debian amd64. > > The NAT gateway is a two-NIC box, with one (xn0) configured with a > public Internet address and the other (xn1) configured with a class A > private address (10.0.0.254). > The Internet traffic is very good from my FreeBSD NAT gateway to the > Internet (~ 50MiB/s) and also between other VMs on the private network > (~ 70MiB/s trough scp) after applying the patch here > (http://firstname.lastname@example.org/msg00855.html) > fixing the "too many frags" problem. > > Here is a schema of my setup with the observed net speed on it: > > ---------- --------------- ---------------------- > |Internet|---xn0---|FBSD DomU NAT|---xn1---|FBSD and Linux DomUs| > ---------- --------------- ---------------------- > <-------> <-------> > 50MiB/s 70MiB/s > > <-------------------------------> > 0KiB/s <network speed< 5 KiB/s > > I tried doing NAT on the FBSD gateway with PF and also with NATd after > shutting down PF and unloaded the kernel modules pf.ko and pflog.ko, but > I have the same perf problems with both solutions. Also I tried > disabling net.inet.tcp.tso and did ifconfig -tso on all NICs on NAT > gateway and other VMs without change. > > I don't see anything on the error console or in /var/log/message. > > When i'm trying going though NAT with a Linux paravirt DomU, the network > perf is slightly better but don't go over 5KiB/s. > > Finally I put my Linux paravirt DomU VM as a NAT gateway in place of the > FreeBSD one, and the network perf is now normal through it (50MiB/s) > from the FreeBSD DomU VMs. > > As I'm very happy with FreeBSD for my environment I'd like to keep as > much as this lovely OS for all my needs, so if anyone have an idea where > the problem can lies, and what to test next to have a clue of what's > happening, I will be very thankfull. > > Thanks in advance. > > -- > /Regards,/ > > *Laurent Cligny > /Founder/* > 02 97 37 71 14 > 06 25 40 86 48 > laurent.cli...@steadinet.fr > > Steadinet <http://www.steadinet.fr> > > > _______________________________________________ > email@example.com mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-xen > To unsubscribe, send any mail to "freebsd-xen-unsubscr...@freebsd.org" > > _______________________________________________ firstname.lastname@example.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-xen To unsubscribe, send any mail to "freebsd-xen-unsubscr...@freebsd.org"