On Mon, Feb 19, 2018 at 09:58:30AM +0000, Laurence Pawling via freebsd-xen wrote: > Hi all, > > > > I’m wondering if anyone here has seen this issue before, I’ve spent the last > couple of days troubleshooting: > > > > Platform: > > Host: XenServer 7.0 running on 2 x E2660-v4, 256GB RAM > > Server VM: FreeBSD 11 (tested on 11.0-p15 and 11.1-p6), 2GB RAM (also tested > with 32GB RAM), 1x50GB HDD, 1 x NIC, 2 or more vCPUs in any combination (2 > sockets x 1 core, 1 socket x 2 cores, …) > > Client VM: FreeBSD 11, any configuration of vCPUs, RAM and HDD. > > > > Behaviour: > > Sporadic interruption of TCP sessions when utilising the above machine as a > “server” with “clients” connecting. Looking into the communication with > pcap/Wireshark, you see a TCP Dup Ack sent from both ends, followed by the > client sending an RST packet, terminating the TCP session. We have also seen > evidence of the client sending a Keepalive packet, which is ACK’d by the > server before the RST is sent from the client end. > > > > To recreate: > > On the above VM, perform a vanilla install of nginx: > > pkg install nginx > > service nginx onestart > > Then on a client VM (currently only tested with FreeBSD), run the following > (or similar): > > for i in {1..10000}; do if [ $(curl -s -o /dev/null -w "%{http_code}" > http://10.2.122.71) != 200 ] ; then echo "error"; fi; done > > When vCPUs=1 on the server, I get no errors, when vCPUs>1 I get errors > reported. The frequency of errors *seems* to be proportional to the number of > vCPUs, but they are sporadic with no clear periodicity or pattern, so that is > just anecdotal. Also, the problem seems by far the most prevalent when > communicating between two VMs on the same host, in the same VLAN. Xen still > sends packets via the switch rather than bridging internally between the > interfaces.
When using >1 vCPUs can you set hw.xn.num_queues=1 on /boot/loader.conf and try to reproduce the issue? I'm afraid this is rather related to multiqueue (which is only used if >1 vCPUs). Thanks, Roger. _______________________________________________ freebsd-virtualization@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-virtualization To unsubscribe, send any mail to "freebsd-virtualization-unsubscr...@freebsd.org"